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Lorenzo Stoakes
f225b34f1e mm/mseal: always define VM_SEALED
Patch series "mseal cleanups", v4.

Perform a number of cleanups to the mseal logic.  Firstly, VM_SEALED is
treated differently from every other VMA flag, it really doesn't make
sense to do this, so we start by making this consistent with everything
else.

Next we place the madvise logic where it belongs - in mm/madvise.c.  It
really makes no sense to abstract this elsewhere.  In doing so, we go to
great lengths to explain very clearly the previously very confusing logic
as to what sealed mappings are impacted here.

In doing so, we retain existing logic regarding treatment of madvise()
discard operations for a sealed, read-only MAP_PRIVATE file-backed
mapping.  This is something we likely need to revisit.

We then abstract out and explain the 'are there are any gaps in this range
in the mm?' check being performed as a prerequisite to mseal being
performed.

Finally, we simplify the actual mseal logic which is really quite
straightforward.

No functional change is intended.


This patch (of 4):

There is no reason to treat VM_SEALED in a special way, in each other case
in which a VMA flag is unavailable due to configuration, we simply assign
that flag to VM_NONE, so make VM_SEALED consistent with all other VMA
flags in this respect.

Additionally, use the next available bit for VM_SEALED, 42, rather than
arbitrarily putting it at 63 and update the declaration to match all other
VMA flags.

No functional change intended.

Link: https://lkml.kernel.org/r/cover.1753431105.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/aeb398a77029b6e7377cd944328bc9bbc3c90537.1753431105.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:09 -07:00
Bijan Tabatabai
dee3ab621f mm/damon/vaddr: skip isolating folios already in destination nid
damos_va_migrate_dests_add() determines the node a folio should be in
based on the struct damos_migrate_dests associated with the migration
scheme and adds the folio to the linked list corresponding to that node so
it can be migrated later.  Currently, folios are isolated and added to the
list even if they are already in the node they should be in.

In using damon weighted interleave more, I've found that the overhead of
needlessly adding these folios to the migration lists can be quite high. 
The overhead comes from isolating folios and placing them in the migration
lists inside of damos_va_migrate_dests_add(), as well as the cost of
handling those folios in damon_migrate_pages().  This patch eliminates
that overhead by simply avoiding the addition of folios that are already
in their intended location to the migration list.

To show the benefit of this patch, we start the test workload and start a
DAMON instance attached to that workload with a migrate_hot scheme that
has one dest field sending data to the local node.  This way, we are only
measuring the overheads of the scheme, and not the cost of migrating
pages, since data will be allocated to the local node by default.  I
tested with two workloads: the embedding reduction workload used in [1]
and a microbenchmark that allocates 20GB of data then sleeps, which is
similar to the memory usage of the embedding reduction workload.

The time taken in damos_va_migrate_dests_add() and damon_migrate_pages()
each aggregation interval is shown below.

Before this patch:
                       damos_va_migrate_dests_add damon_migrate_pages
microbenchmark                   ~2ms                      ~3ms
embedding reduction              ~1s                       ~3s

After this patch:
                       damos_va_migrate_dests_add damon_migrate_pages
microbenchmark                    0us                      ~40us
embedding reduction               0us                      ~100us

I did not do an in depth analysis for why things are much slower in the
embedding reduction workload than the microbenchmark.  However, I assume
it's because the embedding reduction workload oversaturates the bandwidth
of the local memory node, increasing the memory access latency, and in
turn making the pointer chasing involved in iterating through a linked
list much slower.  Regardless of that, this patch results in a significant
speedup.

[1] https://lore.kernel.org/damon/20250709005952.17776-1-bijan311@gmail.com/

Link: https://lkml.kernel.org/r/20250725163300.4602-1-bijan311@gmail.com
Fixes: 19c1dc15c8 ("mm/damon/vaddr: use damos->migrate_dests in migrate_{hot,cold}")
Signed-off-by: Bijan Tabatabai <bijantabatab@micron.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Raghavendra K T <raghavendra.kt@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:09 -07:00
Suresh K C
d6a511dea4 selftests: cachestat: add tests for mmap, refactor and enhance mmap test for cachestat validation
Add a cohesive test case that verifies cachestat behavior with
memory-mapped files using mmap().  Also refactor the test logic to reduce
redundancy, improve error reporting, and clarify failure messages for both
shmem and mmap file types.

[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20250709174657.6916-1-suresh.k.chandrappa@gmail.com
Signed-off-by: Suresh K C <suresh.k.chandrappa@gmail.com>
Reviewed-by: Joshua Hahn <joshua.hahnjy@gmail.com>
Tested-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:09 -07:00
Xuanye Liu
881388f343 mm: add process info to bad rss-counter warning
Enhance the debugging information in check_mm() by including the process
name and PID when reporting bad rss-counter states.  This helps identify
which process is associated with the memory accounting issue.

Link: https://lkml.kernel.org/r/20250723100901.1909683-1-liuqiye2025@163.com
Signed-off-by: Xuanye Liu <liuqiye2025@163.com>
Acked-by: SeongJae Park <sj@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:08 -07:00
Jann Horn
56bdf83de7 kasan: skip quarantine if object is still accessible under RCU
Currently, enabling KASAN masks bugs where a lockless lookup path gets a
pointer to a SLAB_TYPESAFE_BY_RCU object that might concurrently be
recycled and is insufficiently careful about handling recycled objects:
KASAN puts freed objects in SLAB_TYPESAFE_BY_RCU slabs onto its quarantine
queues, even when it can't actually detect UAF in these objects, and the
quarantine prevents fast recycling.

When I introduced CONFIG_SLUB_RCU_DEBUG, my intention was that enabling
CONFIG_SLUB_RCU_DEBUG should cause KASAN to mark such objects as freed
after an RCU grace period and put them on the quarantine, while disabling
CONFIG_SLUB_RCU_DEBUG should allow such objects to be reused immediately;
but that hasn't actually been working.

I discovered such a UAF bug involving SLAB_TYPESAFE_BY_RCU yesterday; I
could only trigger this bug in a KASAN build by disabling
CONFIG_SLUB_RCU_DEBUG and applying this patch.

Link: https://lkml.kernel.org/r/20250723-kasan-tsbrcu-noquarantine-v1-1-846c8645976c@google.com
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:08 -07:00
Joanne Koong
d171b10b2d mm/page-flags: remove folio_start_writeback_keepwrite()
Commit cd57b77197 ("ext4: Convert ext4_bio_write_page() to use a folio)
removed set_page_writeback_keepwrite() which was the last/only caller of
folio_start_writeback_keepwrite().

Link: https://lkml.kernel.org/r/20250722182230.2114587-1-joannelkoong@gmail.com
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:08 -07:00
wang lian
b50e37889f selftests/mm: add process_madvise() tests
Add tests for process_madvise(), focusing on verifying behavior under
various conditions including valid usage and error cases.

[lianux.mm@gmail.com: v7]
  Link: https://lkml.kernel.org/r/20250729113109.12272-1-lianux.mm@gmail.com
Link: https://lkml.kernel.org/r/20250729113109.12272-1-lianux.mm@gmail.com
Link: https://lkml.kernel.org/r/20250721114614.40996-1-lianux.mm@gmail.com
Signed-off-by: wang lian <lianux.mm@gmail.com>
Suggested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Suggested-by: Zi Yan <ziy@nvidia.com>
Suggested-by: Mark Brown <broonie@kernel.org>
Acked-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Zi Yan <ziy@nvidia.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:08 -07:00
Baolin Wang
8d58d65621 mm: shmem: fix the shmem large folio allocation for the i915 driver
After commit acd7ccb284 ("mm: shmem: add large folio support for
tmpfs"), we extend the 'huge=' option to allow any sized large folios for
tmpfs, which means tmpfs will allow getting a highest order hint based on
the size of write() and fallocate() paths, and then will try each
allowable large order.

However, when the i915 driver allocates shmem memory, it doesn't provide
hint information about the size of the large folio to be allocated,
resulting in the inability to allocate PMD-sized shmem, which in turn
affects GPU performance.

Patryk added:

: In my tests, the performance drop ranges from a few percent up to 13%
: in Unigine Superposition under heavy memory usage on the CPU Core Ultra
: 155H with the Xe 128 EU GPU.  Other users have reported performance
: impact up to 30% on certain workloads.  Please find more in the
: regressions reports:
: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14645
: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13845
:
: I believe the change should be backported to all active kernel branches
: after version 6.12.

To fix this issue, we can use the inode's size as a write size hint in
shmem_read_folio_gfp() to help allocate PMD-sized large folios.

Link: https://lkml.kernel.org/r/f7e64e99a3a87a8144cc6b2f1dddf7a89c12ce44.1753926601.git.baolin.wang@linux.alibaba.com
Fixes: acd7ccb284 ("mm: shmem: add large folio support for tmpfs")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reported-by: Patryk Kowalczyk <patryk@kowalczyk.ws>
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Patryk Kowalczyk <patryk@kowalczyk.ws>
Suggested-by: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:05:51 -07:00
Fan Yu
085dece6cc tools/getdelays: add backward compatibility for taskstats version
Add version checks to print_delayacct() to handle differences in struct
taskstats across kernel versions.  Field availability depends on taskstats
version (t->version), corresponding to TASKSTATS_VERSION in kernel headers
(see include/uapi/linux/taskstats.h).

Version feature mapping:
- version >= 11  - supports COMPACT statistics
- version >= 13  - supports WPCOPY statistics
- version >= 14  - supports IRQ statistics
- version >= 16  - supports *_max and *_min delay statistics

This ensures the tool works correctly with both older and newer kernel
versions by conditionally printing fields based on the reported version.

eg.1
bash# grep -r "#define TASKSTATS_VERSION" /usr/include/linux/taskstats.h
"#define TASKSTATS_VERSION       10"
bash# ./getdelays -d -p 1
CPU                 count     real total  virtual total    delay total  delay average
                     7481     3786181709     3807098291       36393725          0.005ms
IO                  count    delay total  delay average
                      369     1116046035          3.025ms
SWAP                count    delay total  delay average
                        0              0          0.000ms
RECLAIM             count    delay total  delay average
                        0              0          0.000ms
THRASHING           count    delay total  delay average
                        0              0          0.000ms

eg.2
bash# grep -r "#define TASKSTATS_VERSION" /usr/include/linux/taskstats.h
"#define TASKSTATS_VERSION       14"
bash# ./getdelays -d -p 1
CPU                 count     real total  virtual total    delay total  delay average
                    68862   163474790046   174584722267    19962496806          0.290ms
IO                  count    delay total  delay average
                        0              0          0.000ms
SWAP                count    delay total  delay average
                        0              0          0.000ms
RECLAIM             count    delay total  delay average
                        0              0          0.000ms
THRASHING           count    delay total  delay average
                        0              0          0.000ms
COMPACT             count    delay total  delay average
                        0              0          0.000ms
WPCOPY              count    delay total  delay average
                        0              0          0.000ms
IRQ                 count    delay total  delay average
                        0              0          0.000ms

Link: https://lkml.kernel.org/r/20250731225326549CttJ7g9NfjTlaqBwl015T@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:41 -07:00
Mike Rapoport (Microsoft)
b753522bed kho: add test for kexec handover
Testing kexec handover requires a kernel driver that will generate some
data and preserve it with KHO on the first boot and then restore that data
and verify it was preserved properly after kexec.

To facilitate such test, along with the kernel driver responsible for data
generation, preservation and restoration add a script that runs a kernel
in a VM with a minimal /init.  The /init enables KHO, loads a kernel image
for kexec and runs kexec reboot.  After the boot of the kexeced kernel,
the driver verifies that the data was properly preserved.

[rppt@kernel.org: fix section mismatch]
  Link: https://lkml.kernel.org/r/aIiRC8fXiOXKbPM_@kernel.org
Link: https://lkml.kernel.org/r/20250727083733.2590139-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:41 -07:00
fan.yu9@zte.com.cn
d92dccd05a delaytop: enhance error logging and add PSI feature description
This patch improves error diagnostics and documentation for delaytop:

1) Enhanced error logging:
   - Added explicit error messages in critical failure paths
   - Implemented BOOL_FPRINT macro for robust output handling

2) PSI feature documentation:
   - Updated header comment to reflect PSI monitoring capability
   - Improved output formatting for PSI information

System Pressure Information: (avg10/avg60/avg300/total)
CPU some:       0.0%/   0.0%/   0.0%/     345(ms)
CPU full:       0.0%/   0.0%/   0.0%/       0(ms)
Memory full:    0.0%/   0.0%/   0.0%/       0(ms)
Memory some:    0.0%/   0.0%/   0.0%/       0(ms)
IO full:        0.0%/   0.0%/   0.0%/      65(ms)
IO some:        0.0%/   0.0%/   0.0%/      79(ms)
IRQ full:       0.0%/   0.0%/   0.0%/       0(ms)

Link: https://lkml.kernel.org/r/202507281628341752gMXCMN7S-Vz_LHYHum9r@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Acked-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:41 -07:00
Colin Ian King
8c54f7e3e0 samples: Kconfig: fix spelling mistake "instancess" -> "instances"
There is a spelling mistake in the SAMPLE_TRACE_ARRAY config. Fix it.

Link: https://lkml.kernel.org/r/20250724111715.141826-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:41 -07:00
OGAWA Hirofumi
fb0e9db99e fat: fix too many log in fat_chain_add()
This log was excessive for a serial console.  So use the ratelimited
version instead.

Link: https://lkml.kernel.org/r/87qzy611d9.fsf@mail.parknet.co.jp
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: syzbot+fa7ef54f66c189c04b73@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=fa7ef54f66c189c04b73
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:40 -07:00
WangYuli
53f433891e scripts/spelling.txt: add notifer||notifier to spelling.txt
This typo was not listed in scripts/spelling.txt, thus it was more
difficult to detect. Add it for convenience.

Link: https://lkml.kernel.org/r/02153C05ED7B49B7+20250722073431.21983-8-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:40 -07:00
WangYuli
004f42dd90 xen/xenbus: fix typo "notifer"
There is a spelling mistake of 'notifer' in the comment which
should be 'notifier'.

Link: https://lkml.kernel.org/r/C6633C66376C709A+20250722073431.21983-7-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:40 -07:00
WangYuli
545040384e net: mvneta: fix typo "notifer"
There is a spelling mistake of 'notifer' in the comment which
should be 'notifier'.

Link: https://lkml.kernel.org/r/0CB4300CB6F49007+20250722073431.21983-4-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:40 -07:00
WangYuli
26197b0fd2 drm/xe: fix typo "notifer"
There is a spelling mistake of 'notifer' in the comment which
should be 'notifier'.

Link: https://lkml.kernel.org/r/94190C5F54A19F3E+20250722073431.21983-3-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:39 -07:00
WangYuli
fbedfb051a cxl: mce: fix typo "notifer"
According to the context, "mce_notifer" should be "mce_notifier".

Link: https://lkml.kernel.org/r/E1EB1BA9FDF07D53+20250722073431.21983-2-wangyuli@uniontech.com
Fixes: 516e5bd0b6 ("cxl: Add mce notifier to emit aliased address for extended linear cache")
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:39 -07:00
WangYuli
a30469cac8 KVM: x86: fix typo "notifer"
Patch series "treewide: Fix typo "notifer"", v3.

There are some spelling mistakes of 'notifer' in comments which
should be 'notifier'.

Fix them and add it to scripts/spelling.txt.


This patch (of 8):

There are some spelling mistakes of 'notifer' which should be 'notifier'.

Link: https://lkml.kernel.org/r/576F0D85F6853074+20250722072734.19367-1-wangyuli@uniontech.com
Link: https://lkml.kernel.org/r/7F05778C3A1A9F8B+20250722073431.21983-1-wangyuli@uniontech.com
Signed-off-by: WangYuli <wangyuli@uniontech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:39 -07:00
Wang Yaxin
1f03d55e5e MAINTAINERS: add maintainers for delaytop
The delaytop tool supports showing system delays and task-level delays,
effectively identifying the top-n tasks with high latency in the system,
which is highly beneficial for improving system performance.  Wang Yaxin
and her colleague Fan Yu focus on locating system delay issues.  To
promote the thriving development of delaytop, we hope to serve as
maintainers to continuously improve it, aiming to provide a more effective
solution for system latency issues in the future.

Link: https://lkml.kernel.org/r/20250721094049958ImB8XG_imntcPqpQn1KfG@zte.com.cn
Signed-off-by: Wang Yaxin <wang.yaxin@zte.com.cn>
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:39 -07:00
Uros Bizjak
58b4fba81a ucount: use atomic_long_try_cmpxchg() in atomic_long_inc_below()
Use atomic_long_try_cmpxchg() instead of
atomic_long_cmpxchg (*ptr, old, new) == old in atomic_long_inc_below().
x86 CMPXCHG instruction returns success in ZF flag, so this change saves
a compare after cmpxchg (and related move instruction in front of cmpxchg).

Also, atomic_long_try_cmpxchg implicitly assigns old *ptr value to "old"
when cmpxchg fails, enabling further code simplifications.

No functional change intended.

Link: https://lkml.kernel.org/r/20250721174610.28361-2-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: Alexey Gladkov <legion@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: MengEn Sun <mengensun@tencent.com>
Cc: "Thomas Weißschuh" <linux@weissschuh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:38 -07:00
Uros Bizjak
f8cd9193b6 ucount: fix atomic_long_inc_below() argument type
The type of u argument of atomic_long_inc_below() should be long to avoid
unwanted truncation to int.

The patch fixes the wrong argument type of an internal function to
prevent unwanted argument truncation.  It fixes an internal locking
primitive; it should not have any direct effect on userspace.

Mark said

: AFAICT there's no problem in practice because atomic_long_inc_below()
: is only used by inc_ucount(), and it looks like the value is
: constrained between 0 and INT_MAX.
: 
: In inc_ucount() the limit value is taken from
: user_namespace::ucount_max[], and AFAICT that's only written by
: sysctls, to the table setup by setup_userns_sysctls(), where
: UCOUNT_ENTRY() limits the value between 0 and INT_MAX.
: 
: This is certainly a cleanup, but there might be no functional issue in
: practice as above.

Link: https://lkml.kernel.org/r/20250721174610.28361-1-ubizjak@gmail.com
Fixes: f9c82a4ea8 ("Increase size of ucounts to atomic_long_t")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: MengEn Sun <mengensun@tencent.com>
Cc: "Thomas Weißschuh" <linux@weissschuh.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:38 -07:00
Alexander Graf
07d2490297 kexec: enable CMA based contiguous allocation
When booting a new kernel with kexec_file, the kernel picks a target
location that the kernel should live at, then allocates random pages,
checks whether any of those patches magically happens to coincide with a
target address range and if so, uses them for that range.

For every page allocated this way, it then creates a page list that the
relocation code - code that executes while all CPUs are off and we are
just about to jump into the new kernel - copies to their final memory
location.  We can not put them there before, because chances are pretty
good that at least some page in the target range is already in use by the
currently running Linux environment.  Copying is happening from a single
CPU at RAM rate, which takes around 4-50 ms per 100 MiB.

All of this is inefficient and error prone.

To successfully kexec, we need to quiesce all devices of the outgoing
kernel so they don't scribble over the new kernel's memory.  We have seen
cases where that does not happen properly (*cough* GIC *cough*) and hence
the new kernel was corrupted.  This started a month long journey to root
cause failing kexecs to eventually see memory corruption, because the new
kernel was corrupted severely enough that it could not emit output to tell
us about the fact that it was corrupted.  By allocating memory for the
next kernel from a memory range that is guaranteed scribbling free, we can
boot the next kernel up to a point where it is at least able to detect
corruption and maybe even stop it before it becomes severe.  This
increases the chance for successful kexecs.

Since kexec got introduced, Linux has gained the CMA framework which can
perform physically contiguous memory mappings, while keeping that memory
available for movable memory when it is not needed for contiguous
allocations.  The default CMA allocator is for DMA allocations.

This patch adds logic to the kexec file loader to attempt to place the
target payload at a location allocated from CMA.  If successful, it uses
that memory range directly instead of creating copy instructions during
the hot phase.  To ensure that there is a safety net in case anything goes
wrong with the CMA allocation, it also adds a flag for user space to force
disable CMA allocations.

Using CMA allocations has two advantages:

  1) Faster by 4-50 ms per 100 MiB. There is no more need to copy in the
     hot phase.
  2) More robust. Even if by accident some page is still in use for DMA,
     the new kernel image will be safe from that access because it resides
     in a memory region that is considered allocated in the old kernel and
     has a chance to reinitialize that component.

Link: https://lkml.kernel.org/r/20250610085327.51817-1-graf@amazon.com
Signed-off-by: Alexander Graf <graf@amazon.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:38 -07:00
Matt Fleming
ed4f142f72 stackdepot: make max number of pools boot-time configurable
We're hitting the WARN in depot_init_pool() about reaching the stack depot
limit because we have long stacks that don't dedup very well.

Introduce a new start-up parameter to allow users to set the number of
maximum stack depot pools.

Link: https://lkml.kernel.org/r/20250718153928.94229-1-matt@readmodwrite.com
Signed-off-by: Matt Fleming <mfleming@cloudflare.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:38 -07:00
Dr. David Alan Gilbert
6c6d8f8ba7 lib/xxhash: remove unused functions
xxh32_digest() and xxh32_update() were added in 2017 in the original
xxhash commit, but have remained unused.

Remove them.

Link: https://lkml.kernel.org/r/20250716133245.243363-1-linux@treblig.org
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dave Gilbert <linux@treblig.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:37 -07:00
Andrew Morton
fefbeed8c6 init/Kconfig: restore CONFIG_BROKEN help text
Linus added it in 2003, it later was removed.  Put it back.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:01:37 -07:00
Kairui Song
5c241ed8d0 mm/shmem, swap: improve cached mTHP handling and fix potential hang
The current swap-in code assumes that, when a swap entry in shmem mapping
is order 0, its cached folios (if present) must be order 0 too, which
turns out not always correct.

The problem is shmem_split_large_entry is called before verifying the
folio will eventually be swapped in, one possible race is:

    CPU1                          CPU2
shmem_swapin_folio
/* swap in of order > 0 swap entry S1 */
  folio = swap_cache_get_folio
  /* folio = NULL */
  order = xa_get_order
  /* order > 0 */
  folio = shmem_swap_alloc_folio
  /* mTHP alloc failure, folio = NULL */
  <... Interrupted ...>
                                 shmem_swapin_folio
                                 /* S1 is swapped in */
                                 shmem_writeout
                                 /* S1 is swapped out, folio cached */
  shmem_split_large_entry(..., S1)
  /* S1 is split, but the folio covering it has order > 0 now */

Now any following swapin of S1 will hang: `xa_get_order` returns 0, and
folio lookup will return a folio with order > 0.  The
`xa_get_order(&mapping->i_pages, index) != folio_order(folio)` will always
return false causing swap-in to return -EEXIST.

And this looks fragile.  So fix this up by allowing seeing a larger folio
in swap cache, and check the whole shmem mapping range covered by the
swapin have the right swap value upon inserting the folio.  And drop the
redundant tree walks before the insertion.

This will actually improve performance, as it avoids two redundant Xarray
tree walks in the hot path, and the only side effect is that in the
failure path, shmem may redundantly reallocate a few folios causing
temporary slight memory pressure.

And worth noting, it may seems the order and value check before inserting
might help reducing the lock contention, which is not true.  The swap
cache layer ensures raced swapin will either see a swap cache folio or
failed to do a swapin (we have SWAP_HAS_CACHE bit even if swap cache is
bypassed), so holding the folio lock and checking the folio flag is
already good enough for avoiding the lock contention.  The chance that a
folio passes the swap entry value check but the shmem mapping slot has
changed should be very low.

Link: https://lkml.kernel.org/r/20250728075306.12704-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20250728075306.12704-2-ryncsn@gmail.com
Fixes: 809bc86517 ("mm: shmem: support large folio swap out")
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 11:53:19 -07:00
Johan Hovold
be71ce9796 drm/bridge: fix OF node leak
Make sure to drop the OF node reference taken when creating the aux
bridge device when the device is later released.

Fixes: 6914968a0b ("drm/bridge: properly refcount DT nodes in aux bridge drivers")
Cc: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250708085124.15445-2-johan@kernel.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
2025-08-02 20:47:16 +03:00
Linus Torvalds
eacf91b0c7 fbdev fixes and cleanups for 6.17-rc1:
Framework fixes:
 - fix potential buffer overflow in do_register_framebuffer() [Yongzhen Zhang]
 
 Driver fixes:
 - imxfb: prevent null-ptr-deref [Chenyuan Yang]
 - nvidiafb: fix build on 32-bit ARCH=um [Johannes Berg]
 - nvidiafb: add depends on HAS_IOPORT [Randy Dunlap]
 - simplefb: Use of_reserved_mem_region_to_resource() for "memory-region" [Rob Herring]
 
 Cleanups:
 - fbcon: various code cleanups wrt blinking [Ville Syrjälä]
 - kyrofb: Convert to devm_*() functions [Giovanni Di Santi]
 - svgalib: Coding style cleanups [Darshan R.]
 - Fix typo in Kconfig text for FB_DEVICE [Daniel Palmer]
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Merge tag 'fbdev-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev

Pull fbdev updates from Helge Deller:
 "One potential buffer overflow fix in the framebuffer registration
  function, some fixes for the imxfb, nvidiafb and simplefb drivers, and
  a bunch of cleanups for fbcon, kyrofb and svgalib.

  Framework fixes:
   - fix potential buffer overflow in do_register_framebuffer() [Yongzhen Zhang]

  Driver fixes:
   - imxfb: prevent null-ptr-deref [Chenyuan Yang]
   - nvidiafb: fix build on 32-bit ARCH=um [Johannes Berg]
   - nvidiafb: add depends on HAS_IOPORT [Randy Dunlap]
   - simplefb: Use of_reserved_mem_region_to_resource() for "memory-region" [Rob Herring]

  Cleanups:
   - fbcon: various code cleanups wrt blinking [Ville Syrjälä]
   - kyrofb: Convert to devm_*() functions [Giovanni Di Santi]
   - svgalib: Coding style cleanups [Darshan R.]
   - Fix typo in Kconfig text for FB_DEVICE [Daniel Palmer]"

* tag 'fbdev-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbcon: Use 'bool' where appopriate
  fbcon: Introduce get_{fg,bg}_color()
  fbcon: fbcon_is_inactive() -> fbcon_is_active()
  fbcon: fbcon_cursor_noblink -> fbcon_cursor_blink
  fbdev: Fix typo in Kconfig text for FB_DEVICE
  fbdev: imxfb: Check fb_add_videomode to prevent null-ptr-deref
  fbdev: svgalib: Clean up coding style
  fbdev: kyro: Use devm_ioremap_wc() for screen mem
  fbdev: kyro: Use devm_ioremap() for mmio registers
  fbdev: kyro: Add missing PCI memory region request
  fbdev: simplefb: Use of_reserved_mem_region_to_resource() for "memory-region"
  fbdev: fix potential buffer overflow in do_register_framebuffer()
  fbdev: nvidiafb: add depends on HAS_IOPORT
  fbdev: nvidiafb: fix build on 32-bit ARCH=um
2025-08-02 09:58:11 -07:00
Linus Torvalds
7061835997 firewire updates for v6.17
This update replaces the remaining tasklet usage in the FireWire subsystem
 with workqueue for asynchronous packet transmission. With this change,
 tasklets are now fully eliminated from the subsystem.
 
 Asynchronous packet transmission is used for serial bus topology
 management as well as for the operation of the SBP-2 protocol driver
 (firewire-sbp2). To ensure reliability during low-memory conditions, the
 associated workqueue is created with the WQ_MEM_RECLAIM flag, allowing it
 to participate in memory reclaim paths. Other attributes are aligned with
 those used for isochronous packet handling, which was migrated to
 workqueues in v6.12.
 
 The workqueues are sleepable and support preemptible work items, making
 them more suitable for real-time workloads that benefit from timely task
 preemption at the system level.
 
 There remains an issue where 'schedule()' may be called within an RCU
 read-side critical section, due to a direct replacement of
 'tasklet_disable_in_atomic()' with 'disable_work_sync()'. A proposed fix
 for this has been posted[1], and is currently under review and testing.
 It is expected to be sent upstream later.
 
  [1] https://lore.kernel.org/lkml/20250728015125.17825-1-o-takashi@sakamocchi.jp/
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Merge tag 'firewire-updates-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394

Pull firewire updates from Takashi Sakamoto:
 "This update replaces the remaining tasklet usage in the FireWire
  subsystem with workqueue for asynchronous packet transmission. With
  this change, tasklets are now fully eliminated from the subsystem.

  Asynchronous packet transmission is used for serial bus topology
  management as well as for the operation of the SBP-2 protocol driver
  (firewire-sbp2). To ensure reliability during low-memory conditions,
  the associated workqueue is created with the WQ_MEM_RECLAIM flag,
  allowing it to participate in memory reclaim paths. Other attributes
  are aligned with those used for isochronous packet handling, which was
  migrated to workqueues in v6.12.

  The workqueues are sleepable and support preemptible work items,
  making them more suitable for real-time workloads that benefit from
  timely task preemption at the system level.

  There remains an issue where 'schedule()' may be called within an RCU
  read-side critical section, due to a direct replacement of
  'tasklet_disable_in_atomic()' with 'disable_work_sync()'. A proposed
  fix for this has been posted[1], and is currently under review and
  testing. It is expected to be sent upstream later"

Link: https://lore.kernel.org/lkml/20250728015125.17825-1-o-takashi@sakamocchi.jp/ [1]

* tag 'firewire-updates-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
  firewire: ohci: reduce the size of common context structure by extracting members into AT structure
  firewire: core: minor code refactoring to localize table of gap count
  firewire: ohci: use workqueue to handle events of AT request/response contexts
  firewire: ohci: use workqueue to handle events of AR request/response contexts
  firewire: core: allocate workqueue for AR/AT request/response contexts
  firewire: core: use from_work() macro to expand parent structure of work_struct
  firewire: ohci: use from_work() macro to expand parent structure of work_struct
  firewire: ohci: correct code comments about bus_reset tasklet
2025-08-02 09:52:53 -07:00
Eduard Zingerman
1b30d44417 bpf: Fix memory leak of bpf_scc_info objects
env->scc_info array contains references to bpf_scc_info objects
allocated lazily in verifier.c:scc_visit_alloc().
env->scc_cnt was supposed to track env->scc_info array size
in order to free referenced objects in verifier.c:free_states().
Fix initialization of env->scc_cnt that was omitted in
verifier.c:compute_scc().

To reproduce the bug:
- build with CONFIG_DEBUG_KMEMLEAK
- boot and load bpf program with loops, e.g.:
  ./veristat -q pyperf180.bpf.o
- initiate memleak scan and check results:
  echo scan > /sys/kernel/debug/kmemleak
  cat /sys/kernel/debug/kmemleak

Fixes: c9e31900b5 ("bpf: propagate read/precision marks over state graph backedges")
Reported-by: Jens Axboe <axboe@kernel.dk>
Closes: https://lore.kernel.org/bpf/CAADnVQKXUWg9uRCPD5ebRXwN4dmBCRUFFM7kN=GxymYz3zU25A@mail.gmail.com/T/
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Tested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250801232330.1800436-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-02 09:04:57 -07:00
Sean Anderson
0808da36b9 ALSA: usb-audio: Don't use printk_ratelimit for debug prints
printk_ratelimit is deprecated, since it shares state with all other
printk sites. Additionally, the suppression message is printed at
warning level even though the actual messages are printed at debug and
are (usually) invisible! This can result in thousands of messages like

retire_capture_urb: 4992 callbacks suppressed

in the console, and can inhibit debugging since it is unclear what the
source of the suppressed callbacks is.

Switch to dev_dbg_ratelimited which doesn't print anything unless debug
is enabled.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Link: https://patch.msgid.link/20250801154710.739464-1-sean.anderson@linux.dev
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2025-08-02 16:17:50 +02:00
Thomas Gleixner
e703b7e247 futex: Move futex cleanup to __mmdrop()
Futex hash allocations are done in mm_init() and the cleanup happens in
__mmput(). That works most of the time, but there are mm instances which
are instantiated via mm_alloc() and freed via mmdrop(), which causes the
futex hash to be leaked.

Move the cleanup to __mmdrop().

Fixes: 56180dd20c ("futex: Use RCU-based per-CPU reference counting instead of rcuref_t")
Reported-by: André Draszik <andre.draszik@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: André Draszik <andre.draszik@linaro.org>
Link: https://lore.kernel.org/all/87ldo5ihu0.ffs@tglx
Closes: https://lore.kernel.org/all/0c8cc83bb73abf080faf584f319008b67d0931db.camel@linaro.org
2025-08-02 15:11:52 +02:00
Roman Kisel
83e6384374 smp: Fix spelling in on_each_cpu_cond_mask()'s doc-comment
"boolean" is spelt as "blooean". Fix that.

Signed-off-by: Roman Kisel <romank@linux.microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250722161818.6139-1-romank@linux.microsoft.com
2025-08-02 14:24:50 +02:00
Huacai Chen
0a91336e28 Merge tag 'bpf-next-6.17' into loongarch-next
LoongArch architecture changes for 6.17 have many bpf features such as
trampoline, so merge 'bpf-next-6.17' to create a base to make bpf work
well.
2025-08-02 11:07:06 +08:00
Tao Chen
f3af62b6ce bpftool: Add bash completion for token argument
This commit updates the bash completion script with the
new token argument.
$ bpftool token
help  list  show

Reviewed-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Link: https://lore.kernel.org/r/20250723144442.1427943-3-chen.dylane@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:03:23 -07:00
Tao Chen
b7f6400849 bpftool: Add bpftool-token manpage
Add bpftool-token manpage with information and examples of token-related
commands.

Suggested-by: Quentin Monnet <qmo@kernel.org>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Link: https://lore.kernel.org/r/20250723144442.1427943-2-chen.dylane@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:03:23 -07:00
Tao Chen
2d812311c2 bpftool: Add bpf_token show
Add `bpftool token show` command to get token info
from bpffs in /proc/mounts.

Example plain output for `token show`:
token_info  /sys/fs/bpf/token
	allowed_cmds:
	  map_create          prog_load
	allowed_maps:
	allowed_progs:
	  kprobe
	allowed_attachs:
	  xdp
token_info  /sys/fs/bpf/token2
	allowed_cmds:
	  map_create          prog_load
	allowed_maps:
	allowed_progs:
	  kprobe
	allowed_attachs:
	  xdp

Example json output for `token show`:
[{
	"token_info": "/sys/fs/bpf/token",
	"allowed_cmds": ["map_create", "prog_load"],
	"allowed_maps": [],
	"allowed_progs": ["kprobe"],
	"allowed_attachs": ["xdp"]
}, {
	"token_info": "/sys/fs/bpf/token2",
	"allowed_cmds": ["map_create", "prog_load"],
	"allowed_maps": [],
	"allowed_progs": ["kprobe"],
	"allowed_attachs": ["xdp"]
}]

Reviewed-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Link: https://lore.kernel.org/r/20250723144442.1427943-1-chen.dylane@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:03:23 -07:00
Alexei Starovoitov
e56f416c8e Merge branch 'task-local-data'
Amery Hung says:

====================
Task local data

v6 -> v7
  - Fix typos and improve the clarity of the cover letter (Emil)
  - Some variable naming changes to make it less confusing (Emil)
  - Add retry in tld_obj_init() as bpf_task_storage_get_recur() with
    BPF_LOCAL_STORAGE_GET_F_CREATE can fail if the task local storage
    is also being modified by other threads on the same CPU. This can
    be especially easy to trigger in CI VM that only has two CPUs.

    Adding bpf_preempt_{disable,enable} around bpf_task_storage_get()
    does not solve the problem as other threads competing for the percpu
    counter lock in task local storage may not limit to bpf helpers.
    Some may be calling bpf_task_storage_free() when threads exit.

    There is no good max retry under heavy contention. For the 1st
    selftest in this set, the max retry to guarantee success grows
    linearly with the thread count. A proposal is to remove the percpu
    counter by changing locks in bpf_local_storage to rqspinlock.

    An alternative is to reduce the probability of failure by allowing
    bpf syscall and struct_ops programs to use bpf_task_storage_get()
    instead of the _recur version by modifying bpf_prog_check_recur().
    This does not solve the problem in tracing programs though.

    v6: https://lore.kernel.org/bpf/20250717164842.1848817-1-ameryhung@gmail.com/

* Overview *

This patchset introduces task local data, an abstract storage type
shared between user space and bpf programs for storing data specific to
each task, and implements a library to access it. The goal is to provide
an abstraction + implementation that is efficient in data sharing and
easy to use. The motivating use case is user space hinting with
sched_ext.

* Motivating use case *

CPU schedulers can potentially make a better decision with hints from
user space process. To support experimenting user space hinting with
sched_ext, there needs a mechanism to pass a "per-task hint" from user
space to the bpf scheduler "efficiently".

A bpf feature, UPTR [0], supported by task local storage is introduced
to serve the needs. It allows pinning a user space page to the kernel
through a special field in task local storage map. This patchset further
builds an abstraction on top of it to allow user space and bpf programs
to easily share per-task data.

* Design *

Task local data is built on top of task local storage map and UPTR to
achieve fast per-task data sharing. UPTR is a type of special field
supported in task local storage map value. A user page assigned to a UPTR
will be pinned to the kernel when the map is updated. Therefore, user
space programs can update data that will be seen by bpf programs without
syscalls.

Additionally, unlike most bpf maps, task local data does not require a
static map value definition. This design is driven by sched_ext, which
would like to allow multiple developers to share a storage without the
need to explicitly agree on the layout of it. While a centralized layout
definition would have worked, the friction of synchronizing it across
different repos is not desirable. This simplify code base management and
makes experimenting easier.

* Introduction to task local data library *

Task local data library provides simple APIs for user space and bpf
through two header files, task_local_data.h and task_local_data.bpf.h,
respectively. The diagram below illustrates the basic usage.

First, an entry of data in task local data, we call it a TLD, needs to
be defined in the user space through TLD_DEFINE_KEY() with information
including the size and the name. The macro will define a global variable
key of opaque type tld_key_t associated with the TLD and initialize it.
Then, the user space program can locate the TLD by passing the key to
tld_get_data() in different thread, where fd is the file descriptor of
the underlying task local storage map. The API returns a pointer to the
TLD specific to the calling thread and will remain valid until the
thread exits. Finally, user space programs can directly read/write the
TLD without bpf syscalls.

To use task local storage on the bpf side, struct tld_keys, needs to
be defined first. The structure that will be used to create tld_key_map
should contain the keys to the TLDs used in a bpf program. In the bpf
program, tld_init_object() first needs to be called to initialize a
struct tld_object variable on the stack. Then, tld_get_data() can be
called to get a pointer to the TLD similar to the user space. The API
will use the name to lookup task local data and cache the key in task
local storage map, tld_key_map, to speed up subsequent access. The size
of the TLD is also needed to prevent out-of-bound access in bpf.

 ┌─ Application ───────────────────────────────────────────────────────┐
 │ TLD_DEFINE_KEY(kx, "X", 4);      ┌─ library A ─────────────────────┐│
 │                                  │ void func(...)                  ││
 │ int main(...)                    │ {                               ││
 │ {                                │     tld_key_t ky;               ││
 │      int *x;                     │     bool *y;                    ││
 │                                  │                                 ││
 │      x = tld_get_data(fd, kx);   │     ky = tld_create_key("Y", 1);││
 │      if (x) *x = 123;            │     y = tld_get_data(fd, ky);   ││
 │                         ┌────────┤     if (y) *y = true;           ││
 │                         │        └─────────────────────────────────┘│
 └───────┬─────────────────│───────────────────────────────────────────┘
         V                 V
 + ─ Task local data ─ ─ ─ ─ ─ +  ┌─ BPF program ──────────────────────┐
 | ┌─ tld_data_map ──────────┐ |  │ struct tld_object obj;             │
 | │ BPF Task local storage  │ |  │ bool *y;                           │
 | │                         │ |  │ int *x;                            │
 | │ tld_data_u __uptr *data │ |  │                                    │
 | │ tld_meta_u __uptr *meta │ |  │ if (tld_init_object(task, &obj))   │
 | └─────────────────────────┘ |  │     return 0;                      │
 | ┌─ tld_key_map ───────────┐ |  │                                    │
 | │ BPF Task local storage  │ |  │ x = tld_get_data(&obj, kx, "X", 4);│
 | │                         │ |<─┤ if (x) /* do something */          │
 | │ tld_key_t kx;           │ |  │                                    │
 | │ tld_key_t ky;           │ |  │ y = tld_get_data(&obj, ky, "Y", 1);│
 | └─────────────────────────┘ |  │ if (y) /* do something */          │
 + ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ +  └────────────────────────────────────┘

* Implementation *

Task local data defines the storage to be a task local storage map with
two UPTRs pointing to tld_data_u and tld_meta_u. tld_data_u, individual
to each thread, contains TLD data and the starting offset of data in a
page. tld_meta_u, shared by threads in a process, consists of the TLD
counts, total size of TLDs and tld_metadata for each TLD. tld_metadata
contains the name and the size of a TLD.

  struct tld_data_u {
          u64 start;
          char data[PAGE_SIZE - sizeof(u64)];
  };

  struct tld_meta_u {
          u8 cnt;
          u16 size;
          struct metadata metadata[TLD_DATA_CNT];
  };

Both user space and bpf API follow the same protocol when accessing
task local data. A pointer to a TLD is located using a key. The key is
effectively the offset of a TLD in tld_data_u->data. To define a new
TLD, the user space API TLD_DEFINE_KEY() iterates tld_meta_u->metadata
until an empty slot is found and then update it. It also adds up sizes
of prior TLDs to derive the offset (i.e., key). Then, to locate a TLD,
tld_get_data() can simply return tld_data_u->data + offset.

To locate a TLD in bpf programs, an API with the same name as the user
space, tld_get_data() can be called. It takes more effort in the first
invocation as it fetches the key by name. Internal helper,
__tld_fetch_key() will iterate tld_meta_u->metadata until the name is
found. Then, the offset is cached as key in another task local storage
map, tld_key_map. When the search fails, the current TLD count is
cached instead to skip searching metadata entries that has been searched
in future invocation. The detail of task local data operations can be
found in patch 1.

* Misc *

The metadata can potentially use run-length encoding for names to reduce
memory wastage and support save more TLDs. I have a version that works,
but the selftest takes a bit longer to finish. More investigation needed
to find the root cause. I will save this for the future when there is a
need to store more than 63 TLDs.

[0] https://lore.kernel.org/bpf/20241023234759.860539-1-martin.lau@linux.dev/
---

v5 -> v6
  - Address Andrii's comment
  - Fix verification failure in no_alu32
  - Some cleanup
  v5: https://lore.kernel.org/bpf/20250627233958.2602271-1-ameryhung@gmail.com/

v4 -> v5
  - Add an option to free memory on thread exit to prevent memory leak
  - Add an option to reduce memory waste if the allocator can
    use just enough memory to fullfill aligned_alloc() (e.g., glibc)
  - Tweak bpf API
      - Remove tld_fetch_key() as it does not work in init_tasl
      - tld_get_data() now tries to fetch key if it is not cached yet
  - Optimize bpf side tld_get_data()
      - Faster fast path
      - Less code
  - Use stdatomic.h in user space library with seq_cst order
  - Introduce TLD_DEFINE_KEY() as the default TLD creation API for
    easier memory management.
      - TLD_DEFINE_KEY() can consume memory up to a page and no memory
        is wasted since their size is known before per-thread data
        allocation.
      - tld_create_key() can only use up to TLD_DYN_DATA_SIZE. Since
        tld_create_key can run any time even after per-thread data
        allocation, it is impossible to predict the total size. A
        configurable size of memory is allocated on top of the total
        size of TLD_DEFINE_KEY() to accommodate dynamic key creation.
  - Add tld prefix to all macros
  - Replace map_update(NO_EXIST) in __tld_init_data() with cmpxchg()
  - No more +1,-1 dance on the bpf side
  - Reduce printf from ASSERT in race test
  - Try implementing run-length encoding for name and decide to
    save it for the future
  v4: https://lore.kernel.org/bpf/20250515211606.2697271-1-ameryhung@gmail.com/

v3 -> v4
  - API improvements
      - Simplify API
      - Drop string obfuscation
      - Use opaque type for key
      - Better documentation
  - Implementation
      - Switch to dynamic allocation for per-task data
      - Now offer as header-only libraries
      - No TLS map pinning; leave it to users
  - Drop pthread dependency
  - Add more invalid tld_create_key() test
  - Add a race test for tld_create_key()
  v3: https://lore.kernel.org/bpf/20250425214039.2919818-1-ameryhung@gmail.com/

---
====================

Link: https://patch.msgid.link/20250730185903.3574598-1-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:00:47 -07:00
Amery Hung
7841811417 selftests/bpf: Test concurrent task local data key creation
Test thread-safety of tld_create_key(). Since tld_create_key() does
not rely on locks but memory barriers and atomic operations to protect
the shared metadata, the thread-safety of the function is non-trivial.
Make sure concurrent tld_key_create(), both valid and invalid, can not
race and corrupt metatada, which may leads to TLDs not being thread-
specific or duplicate TLDs with the same name.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20250730185903.3574598-5-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:00:46 -07:00
Amery Hung
120f1a950e selftests/bpf: Test basic task local data operations
Test basic operations of task local data with valid and invalid
tld_create_key().

For invalid calls, make sure they return the right error code and check
that the TLDs are not inserted by running tld_get_data("
value_not_exists") on the bpf side. The call should a null pointer.

For valid calls, first make sure the TLDs are created by calling
tld_get_data() on the bpf side. The call should return a valid pointer.

Finally, verify that the TLDs are indeed task-specific (i.e., their
addresses do not overlap) with multiple user threads. This done by
writing values unique to each thread, reading them from both user space
and bpf, and checking if the value read back matches the value written.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20250730185903.3574598-4-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:00:46 -07:00
Amery Hung
31e838e1cd selftests/bpf: Introduce task local data
Task local data defines an abstract storage type for storing task-
specific data (TLD). This patch provides user space and bpf
implementation as header-only libraries for accessing task local data.

Task local data is a bpf task local storage map with two UPTRs:

- tld_meta_u, shared by all tasks of a process, consists of the total
  count and size of TLDs and an array of metadata of TLDs. A TLD
  metadata contains the size and name. The name is used to identify a
  specific TLD in bpf programs.

- u_tld_data points to a task-specific memory. It stores TLD data and
  the starting offset of data in a page.

  Task local design decouple user space and bpf programs. Since bpf
  program does not know the size of TLDs in compile time, u_tld_data
  is declared as a page to accommodate TLDs up to a page. As a result,
  while user space will likely allocate memory smaller than a page for
  actual TLDs, it needs to pin a page to kernel. It will pin the page
  that contains enough memory if the allocated memory spans across the
  page boundary.

The library also creates another task local storage map, tld_key_map,
to cache keys for bpf programs to speed up the access.

Below are the core task local data API:

                   User space                          BPF
  Define TLD       TLD_DEFINE_KEY(), tld_create_key()  -
  Init TLD object  -                                   tld_object_init()
  Get TLD data     tld_get_data()                      tld_get_data()

- TLD_DEFINE_KEY(), tld_create_key()

  A TLD is first defined by the user space with TLD_DEFINE_KEY() or
  tld_create_key(). TLD_DEFINE_KEY() defines a TLD statically and
  allocates just enough memory during initialization. tld_create_key()
  allows creating TLDs on the fly, but has a fix memory budget,
  TLD_DYN_DATA_SIZE.

  Internally, they all call __tld_create_key(), which iterates
  tld_meta_u->metadata to check if a TLD can be added. The total TLD
  size needs to fit into a page (limit of UPTR), and no two TLDs can
  have the same name. If a TLD can be added, u_tld_meta->cnt is
  increased using cmpxchg as there may be other concurrent
  __tld_create_key(). After a successful cmpxchg, the last available
  tld_meta_u->metadata now belongs to the calling thread. To prevent
  other threads from reading incomplete metadata while it is being
  updated, tld_meta_u->metadata->size is used to signal the completion.

  Finally, the offset, derived from adding up prior TLD sizes is then
  encapsulated as an opaque object key to prevent user misuse. The
  offset is guaranteed to be 8-byte aligned to prevent load/store
  tearing and allow atomic operations on it.

- tld_get_data()

  User space programs can pass the key to tld_get_data() to get a
  pointer to the associated TLD. The pointer will remain valid for the
  lifetime of the thread.

  tld_data_u is lazily allocated on the first call to tld_get_data().
  Trying to read task local data from bpf will result in -ENODATA
  during tld_object_init(). The task-specific memory need to be freed
  manually by calling tld_free() on thread exit to prevent memory leak
  or use TLD_FREE_DATA_ON_THREAD_EXIT.

- tld_object_init() (BPF)

  BPF programs need to call tld_object_init() before calling
  tld_get_data(). This is to avoid redundant map lookup in
  tld_get_data() by storing pointers to the map values on stack.
  The pointers are encapsulated as tld_object.

  tld_key_map is also created on the first time tld_object_init()
  is called to cache TLD keys successfully fetched by tld_get_data().

  bpf_task_storage_get(.., F_CREATE) needs to be retried since it may
  fail when another thread has already taken the percpu counter lock
  for the task local storage.

- tld_get_data() (BPF)

  BPF programs can also get a pointer to a TLD with tld_get_data().
  It uses the cached key in tld_key_map to locate the data in
  tld_data_u->data. If the cached key is not set yet (<= 0),
  __tld_fetch_key() will be called to iterate tld_meta_u->metadata
  and find the TLD by name. To prevent redundant string comparison
  in the future when the search fail, the tld_meta_u->cnt is stored
  in the non-positive range of the key. Next time, __tld_fetch_key()
  will be called only if there are new TLDs and the search will start
  from the newly added tld_meta_u->metadata using the old
  tld_meta_u-cnt.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20250730185903.3574598-3-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:00:46 -07:00
Amery Hung
86de56487e bpf: Allow syscall bpf programs to call non-recur helpers
Allow syscall programs to call non-recur helpers too since syscall bpf
programs runs in process context through bpf syscall, BPF_PROG_TEST_RUN,
and cannot run recursively.

bpf_task_storage_{get,set} have "_recur" versions that call trylock
instead of taking the lock directly to avoid deadlock when called by
bpf programs that run recursively. Currently, only bpf_lsm, bpf_iter,
struct_ops without private stack are allow to call the non-recur helpers
since they cannot be recursively called in another bpf program.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20250730185903.3574598-2-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-08-01 18:00:46 -07:00
Linus Torvalds
a6923c06a3 bpf-fixes
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Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Pull bpf fixes from Alexei Starovoitov:

 - Fix kCFI failures in JITed BPF code on arm64 (Sami Tolvanen, Puranjay
   Mohan, Mark Rutland, Maxwell Bland)

 - Disallow tail calls between BPF programs that use different cgroup
   local storage maps to prevent out-of-bounds access (Daniel Borkmann)

 - Fix unaligned access in flow_dissector and netfilter BPF programs
   (Paul Chaignon)

 - Avoid possible use of uninitialized mod_len in libbpf (Achill
   Gilgenast)

* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Test for unaligned flow_dissector ctx access
  bpf: Improve ctx access verifier error message
  bpf: Check netfilter ctx accesses are aligned
  bpf: Check flow_dissector ctx accesses are aligned
  arm64/cfi,bpf: Support kCFI + BPF on arm64
  cfi: Move BPF CFI types and helpers to generic code
  cfi: add C CFI type macro
  libbpf: Avoid possible use of uninitialized mod_len
  bpf: Fix oob access in cgroup local storage
  bpf: Move cgroup iterator helpers to bpf.h
  bpf: Move bpf map owner out of common struct
  bpf: Add cookie object to bpf maps
2025-08-01 17:13:26 -07:00
Linus Torvalds
f4f346c346 [GIT PULL] perf tools changes for v6.17
Build-ID processing goodies
 ---------------------------
 Build-IDs are content based hashes to link regions of memory to ELF files
 in post processing. They have been available in distros for quite a while:
 
     $ file /bin/bash
     /bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
     dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
     BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
     for GNU/Linux 3.2.0, stripped
 
 It is possible to ask the kernel to get it from mmap executable backing
 storage at time they are being put in place and send it as metadata at
 that moment to have in perf.data.
 
 Prefer that across the board to speed up 'record' time - it post processes
 the samples to find binaries touched by any samples and to save them with
 build-ID.  It can skip reading build-ID in userspace if it comes from the
 kernel.
 
 perf record
 -----------
 * Make --buildid-mmap default.  The kernel can generate MMAP2 events
   with a build-ID from ELF header.  Use that by default instead of using
   inode and device ID to identify binaries.  It also can be disabled
   with --no-buildid-mmap.
 
 * Use BPF for -u/--uid option to sample processes belong to a user.
   BPF can track user processes more accurately and the existing logic
   often fails to get the list of processes due to race with reading the
   /proc filesystem.
 
 * Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
   they have variables starting with "bpf_metadata_".  This will help to
   identify BPF objects used in the profile.  This has been supported in
   bpftool for some time and allows the recording of metadata such as
   commit hashes, versions, etc, that now gets recorded in perf.data as
   well.
 
 * Collect list of DSOs touched in the sample callchains as well as in
   the sample itself.  This would increase the processing time at the end
   of record, but can improve the data quality.
 
 perf stat
 ---------
 * Add a new 'drm' pseudo-PMU support like in 'hwmon'.  It can collect
   DRM usage stats using fdinfo in /proc.
 
   On my Intel laptop, it shows like below:
 
     $ perf list drm
     ...
 
     drm:
       drm-active-stolen-system0
            [Total memory active in one or more engines. Unit: drm_i915]
       drm-active-system0
            [Total memory active in one or more engines. Unit: drm_i915]
       drm-engine-capacity-video
            [Engine capacity. Unit: drm_i915]
       drm-engine-copy
            [Utilization in ns. Unit: drm_i915]
       drm-engine-render
            [Utilization in ns. Unit: drm_i915]
       drm-engine-video
            [Utilization in ns. Unit: drm_i915]
       ...
 
     $ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1
 
      Performance counter stats for 'system wide':
 
     48,137,316,988,873 ns       drm-engine-render
         34,452,696,746 ns       drm-engine-video
                     20 capacity drm-engine-capacity-video
 
            1.002086194 seconds time elapsed
 
 perf list
 ---------
 * Add description for software events.  The description is in JSON format
   and the event parser now can handle the software events like others
   (for example, it's case-insensitive and subject to wildcard matching).
 
     $ perf list software
 
     List of pre-defined events (to be used in -e or -M):
 
     software:
       alignment-faults
            [Number of kernel handled memory alignment faults. Unit: software]
       bpf-output
            [An event used by BPF programs to write to the perf ring buffer. Unit: software]
       cgroup-switches
            [Number of context switches to a task in a different cgroup. Unit: software]
       context-switches
            [Number of context switches [This event is an alias of cs]. Unit: software]
       cpu-clock
            [Per-CPU high-resolution timer based event. Unit: software]
       cpu-migrations
            [Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
       cs
            [Number of context switches [This event is an alias of context-switches]. Unit: software]
       dummy
            [A placeholder event that doesn't count anything. Unit: software]
       emulation-faults
            [Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
       faults
            [Number of page faults [This event is an alias of page-faults]. Unit: software]
       major-faults
            [Number of major page faults. Major faults require I/O to handle. Unit: software]
       migrations
            [Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
       minor-faults
            [Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
       page-faults
            [Number of page faults [This event is an alias of faults]. Unit: software]
       task-clock
            [Per-task high-resolution timer based event. Unit: software]
 
 perf ftrace
 -----------
 * Add -e/--events option to perf ftrace latency to measure latency
   between the two events instead of a function.
 
     $ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
     #   DURATION     |      COUNT | GRAPH                                |
        256 -  512 us |          4 | ######                               |
          2 -    4 ms |          2 | ###                                  |
          4 -    8 ms |         12 | ###################                  |
          8 -   16 ms |         10 | ################                     |
 
     # statistics  (in usec)
       total time:               194915
         avg time:                 6961
         max time:                12855
         min time:                  373
            count:                   28
 
 * Add new function graph tracer options (--graph-opts) to display more
   info like arguments and return value.  They will be passed to the
   kernel ftrace directly.
 
     $ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
     # tracer: function_graph
     #
     # CPU  DURATION                  FUNCTION CALLS
     # |     |   |                     |   |   |   |
     ...
     5)               |  mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */
     5)   0.188 us    |    local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
     5)               |    rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */
     5)               |      _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */
     5)   0.123 us    |        preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
     5)   0.128 us    |        local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
     5)   0.086 us    |        do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
     5)   0.845 us    |      } /* _raw_spin_lock_irqsave ret=0x292 */
     ...
 
 misc
 ----
 * Add perf archive --exclude-buildids <FILE> option to skip some binaries.
   The format of the FILE should be same as an output of perf buildid-list.
 
 * Get rid of dependency of libcrypto.  It was just to get SHA-1 hash so
   implement it directly like in the kernel.  A side effect is that it
   needs -fno-strict-aliasing compiler option (again, like in the kernel).
 
 * Convert all shell script tests to use bash.
 
 Reviewed-by: Arnaldo Carvalho de Melo <acme@kernel.org>
 Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Merge tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

Pull perf tools updates from Namhyung Kim:
 "Build-ID processing goodies:

     Build-IDs are content based hashes to link regions of memory to ELF
     files in post processing. They have been available in distros for
     quite a while:

       $ file /bin/bash
       /bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
       dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
       BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
       for GNU/Linux 3.2.0, stripped

     It is possible to ask the kernel to get it from mmap executable
     backing storage at time they are being put in place and send it as
     metadata at that moment to have in perf.data.

     Prefer that across the board to speed up 'record' time - it post
     processes the samples to find binaries touched by any samples and
     to save them with build-ID. It can skip reading build-ID in
     userspace if it comes from the kernel.

  perf record:

   * Make --buildid-mmap default.  The kernel can generate MMAP2 events
     with a build-ID from ELF header.  Use that by default instead of using
     inode and device ID to identify binaries.  It also can be disabled
     with --no-buildid-mmap.

   * Use BPF for -u/--uid option to sample processes belong to a user.
     BPF can track user processes more accurately and the existing logic
     often fails to get the list of processes due to race with reading the
     /proc filesystem.

   * Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
     they have variables starting with "bpf_metadata_".  This will help to
     identify BPF objects used in the profile.  This has been supported in
     bpftool for some time and allows the recording of metadata such as
     commit hashes, versions, etc, that now gets recorded in perf.data as
     well.

   * Collect list of DSOs touched in the sample callchains as well as in
     the sample itself.  This would increase the processing time at the end
     of record, but can improve the data quality.

  perf stat:

   * Add a new 'drm' pseudo-PMU support like in 'hwmon'.  It can collect
     DRM usage stats using fdinfo in /proc.

     On my Intel laptop, it shows like below:

       $ perf list drm
       ...

       drm:
         drm-active-stolen-system0
              [Total memory active in one or more engines. Unit: drm_i915]
         drm-active-system0
              [Total memory active in one or more engines. Unit: drm_i915]
         drm-engine-capacity-video
              [Engine capacity. Unit: drm_i915]
         drm-engine-copy
              [Utilization in ns. Unit: drm_i915]
         drm-engine-render
              [Utilization in ns. Unit: drm_i915]
         drm-engine-video
              [Utilization in ns. Unit: drm_i915]
         ...

       $ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1

        Performance counter stats for 'system wide':

       48,137,316,988,873 ns       drm-engine-render
           34,452,696,746 ns       drm-engine-video
                       20 capacity drm-engine-capacity-video

              1.002086194 seconds time elapsed

  perf list

   * Add description for software events.  The description is in JSON format
     and the event parser now can handle the software events like others
     (for example, it's case-insensitive and subject to wildcard matching).

       $ perf list software

       List of pre-defined events (to be used in -e or -M):

       software:
         alignment-faults
              [Number of kernel handled memory alignment faults. Unit: software]
         bpf-output
              [An event used by BPF programs to write to the perf ring buffer. Unit: software]
         cgroup-switches
              [Number of context switches to a task in a different cgroup. Unit: software]
         context-switches
              [Number of context switches [This event is an alias of cs]. Unit: software]
         cpu-clock
              [Per-CPU high-resolution timer based event. Unit: software]
         cpu-migrations
              [Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
         cs
              [Number of context switches [This event is an alias of context-switches]. Unit: software]
         dummy
              [A placeholder event that doesn't count anything. Unit: software]
         emulation-faults
              [Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
         faults
              [Number of page faults [This event is an alias of page-faults]. Unit: software]
         major-faults
              [Number of major page faults. Major faults require I/O to handle. Unit: software]
         migrations
              [Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
         minor-faults
              [Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
         page-faults
              [Number of page faults [This event is an alias of faults]. Unit: software]
         task-clock
              [Per-task high-resolution timer based event. Unit: software]

  perf ftrace:

   * Add -e/--events option to perf ftrace latency to measure latency
     between the two events instead of a function.

       $ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
       #   DURATION     |      COUNT | GRAPH                                |
          256 -  512 us |          4 | ######                               |
            2 -    4 ms |          2 | ###                                  |
            4 -    8 ms |         12 | ###################                  |
            8 -   16 ms |         10 | ################                     |

       # statistics  (in usec)
         total time:               194915
           avg time:                 6961
           max time:                12855
           min time:                  373
              count:                   28

   * Add new function graph tracer options (--graph-opts) to display more
     info like arguments and return value.  They will be passed to the
     kernel ftrace directly.

       $ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
       # tracer: function_graph
       #
       # CPU  DURATION                  FUNCTION CALLS
       # |     |   |                     |   |   |   |
       ...
       5)               |  mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */
       5)   0.188 us    |    local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
       5)               |    rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */
       5)               |      _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */
       5)   0.123 us    |        preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
       5)   0.128 us    |        local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
       5)   0.086 us    |        do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
       5)   0.845 us    |      } /* _raw_spin_lock_irqsave ret=0x292 */
       ...

  Misc:

   * Add perf archive --exclude-buildids <FILE> option to skip some binaries.
     The format of the FILE should be same as an output of perf buildid-list.

   * Get rid of dependency of libcrypto.  It was just to get SHA-1 hash so
     implement it directly like in the kernel.  A side effect is that it
     needs -fno-strict-aliasing compiler option (again, like in the kernel).

   * Convert all shell script tests to use bash"

* tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits)
  perf record: Cache build-ID of hit DSOs only
  perf test: Ensure lock contention using pipe mode
  perf python: Stop using deprecated PyUnicode_AsString()
  perf list: Skip ABI PMUs when printing pmu values
  perf list: Remove tracepoint printing code
  perf tp_pmu: Add event APIs
  perf tp_pmu: Factor existing tracepoint logic to new file
  perf parse-events: Remove non-json software events
  perf jevents: Add common software event json
  perf tools: Remove libtraceevent in .gitignore
  perf test: Fix comment ordering
  perf sort: Use perf_env to set arch sort keys and header
  perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test
  perf sample: Remove arch notion of sample parsing
  perf env: Remove global perf_env
  perf trace: Avoid global perf_env with evsel__env
  perf auxtrace: Pass perf_env from session through to mmap read
  perf machine: Explicitly pass in host perf_env
  perf bench synthesize: Avoid use of global perf_env
  perf top: Make perf_env locally scoped
  ...
2025-08-01 16:55:47 -07:00
Linus Torvalds
0905809b38 parisc architecture fixes for kernel v6.17-rc1:
The parisc kernel wrongly allows reading from read-protected userspace
 memory without faulting, e.g. when userspace uses mprotect() to
 read-protect a memory area and then uses a pointer to this memory in a
 write(2, addr, 1) syscall.  To fix this issue, Dave Anglin developed a
 set of patches which use the proberi assembler instruction to
 additionally check read access permissions at runtime.
 
 Randy Dunlap contributed two patches to fix a minor typo and to explain
 why a 32-bit compiler is needed although a 64-bit kernel is built.
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Merge tag 'parisc-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc updates from Helge Deller:

 - The parisc kernel wrongly allows reading from read-protected
   userspace memory without faulting, e.g. when userspace uses
   mprotect() to read-protect a memory area and then uses a pointer to
   this memory in a write(2, addr, 1) syscall.

   To fix this issue, Dave Anglin developed a set of patches which use
   the proberi assembler instruction to additionally check read access
   permissions at runtime.

 - Randy Dunlap contributed two patches to fix a minor typo and to
   explain why a 32-bit compiler is needed although a 64-bit kernel is
   built

* tag 'parisc-for-6.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Revise __get_user() to probe user read access
  parisc: Revise gateway LWS calls to probe user read access
  parisc: Drop WARN_ON_ONCE() from flush_cache_vmap
  parisc: Try to fixup kernel exception in bad_area_nosemaphore path of do_page_fault()
  parisc: Define and use set_pte_at()
  parisc: Rename pte_needs_flush() to pte_needs_cache_flush() in cache.c
  parisc: Check region is readable by user in raw_copy_from_user()
  parisc: Update comments in make_insert_tlb
  parisc: Makefile: explain that 64BIT requires both 32-bit and 64-bit compilers
  parisc: Makefile: fix a typo in palo.conf
2025-08-01 16:15:53 -07:00
Steven Rostedt
3ca824369b tracing: Have unsigned int function args displayed as hexadecimal
Most function arguments that are passed in as unsigned int or unsigned
long are better displayed as hexadecimal than normal integer. For example,
the functions:

static void __create_object(unsigned long ptr, size_t size,
				int min_count, gfp_t gfp, unsigned int objflags);

static bool stack_access_ok(struct unwind_state *state, unsigned long _addr,
			    size_t len);

void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);

Show up in the trace as:

    __create_object(ptr=-131387050520576, size=4096, min_count=1, gfp=3264, objflags=0) <-kmem_cache_alloc_noprof
    stack_access_ok(state=0xffffc9000233fc98, _addr=-60473102566256, len=8) <-unwind_next_frame
    __local_bh_disable_ip(ip=-2127311112, cnt=256) <-handle_softirqs

Instead, by displaying unsigned as hexadecimal, they look more like this:

    __create_object(ptr=0xffff8881028d2080, size=0x280, min_count=1, gfp=0x82820, objflags=0x0) <-kmem_cache_alloc_node_noprof
    stack_access_ok(state=0xffffc90000003938, _addr=0xffffc90000003930, len=0x8) <-unwind_next_frame
    __local_bh_disable_ip(ip=0xffffffff8133cef8, cnt=0x100) <-handle_softirqs

Which is much easier to understand as most unsigned longs are usually just
pointers. Even the "unsigned int cnt" in __local_bh_disable_ip() looks
better as hexadecimal as a lot of flags are passed as unsigned.

Changes since v2: https://lore.kernel.org/20250801111453.01502861@gandalf.local.home

- Use btf_int_encoding() instead of open coding it (Martin KaFai Lau)

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Link: https://lore.kernel.org/20250801165601.7770d65c@gandalf.local.home
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-08-01 19:14:51 -04:00
Linus Torvalds
d41e5839d8 cxl for v6.17
- Add documentation template for CXL conventions to document CXL platform quirks
 - Replace mutex_lock_io() with mutex_lock() for mailbox
 - Add location limit for fake CFMWS range for cxl_test, ARM platform enabling
 - CXL documentation typo and clarity fixes
 - Use correct format specifier for function cxl_set_ecs_threshold()
 - Make cxl_bus_type constant
 - Introduce new helper cxl_resource_contains_addr() to check address availability
 - Fix wrong DPA checking for PPR operation
 - Remove core/acpi.c and CXL core dependency on ACPI
 - Introduce ACQUIRE() and ACQUIRE_ERR() for conditional locks
   - Add CXL updates utilizing ACQUIRE() macro to remove gotos and improve
     readability
 - Add return for the dummy version of cxl_decoder_detach() without CONFIG_CXL_REGION
 - CXL events updates for spec r3.2
 - Fix return of __cxl_decoder_detach() error path
 - CXL debugfs documentation fix
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Merge tag 'cxl-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

Pull CXL updates from Dave Jiang:
 "The most significant changes in this pull request is the series that
  introduces ACQUIRE() and ACQUIRE_ERR() macros to replace conditional
  locking and ease the pain points of scoped_cond_guard().

  The series also includes follow on changes that refactor the CXL
  sub-system to utilize the new macros.

  Detail summary:

   - Add documentation template for CXL conventions to document CXL
     platform quirks

   - Replace mutex_lock_io() with mutex_lock() for mailbox

   - Add location limit for fake CFMWS range for cxl_test, ARM platform
     enabling

   - CXL documentation typo and clarity fixes

   - Use correct format specifier for function cxl_set_ecs_threshold()

   - Make cxl_bus_type constant

   - Introduce new helper cxl_resource_contains_addr() to check address
     availability

   - Fix wrong DPA checking for PPR operation

   - Remove core/acpi.c and CXL core dependency on ACPI

   - Introduce ACQUIRE() and ACQUIRE_ERR() for conditional locks

   - Add CXL updates utilizing ACQUIRE() macro to remove gotos and
     improve readability

   - Add return for the dummy version of cxl_decoder_detach() without
     CONFIG_CXL_REGION

   - CXL events updates for spec r3.2

   - Fix return of __cxl_decoder_detach() error path

   - CXL debugfs documentation fix"

* tag 'cxl-for-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: (28 commits)
  Documentation/ABI/testing/debugfs-cxl: Add 'cxl' to clear_poison path
  cxl/region: Fix an ERR_PTR() vs NULL bug
  cxl/events: Trace Memory Sparing Event Record
  cxl/events: Add extra validity checks for CVME count in DRAM Event Record
  cxl/events: Add extra validity checks for corrected memory error count in General Media Event Record
  cxl/events: Update Common Event Record to CXL spec rev 3.2
  cxl: Fix -Werror=return-type in cxl_decoder_detach()
  cleanup: Fix documentation build error for ACQUIRE updates
  cxl: Convert to ACQUIRE() for conditional rwsem locking
  cxl/region: Consolidate cxl_decoder_kill_region() and cxl_region_detach()
  cxl/region: Move ready-to-probe state check to a helper
  cxl/region: Split commit_store() into __commit() and queue_reset() helpers
  cxl/decoder: Drop pointless locking
  cxl/decoder: Move decoder register programming to a helper
  cxl/mbox: Convert poison list mutex to ACQUIRE()
  cleanup: Introduce ACQUIRE() and ACQUIRE_ERR() for conditional locks
  cxl: Remove core/acpi.c and cxl core dependency on ACPI
  cxl/core: Using cxl_resource_contains_addr() to check address availability
  cxl/edac: Fix wrong dpa checking for PPR operation
  cxl/core: Introduce a new helper cxl_resource_contains_addr()
  ...
2025-08-01 15:47:06 -07:00
Sharath Chandra Vurukala
1dbf1d590d net: Add locking to protect skb->dev access in ip_output
In ip_output() skb->dev is updated from the skb_dst(skb)->dev
this can become invalid when the interface is unregistered and freed,

Introduced new skb_dst_dev_rcu() function to be used instead of
skb_dst_dev() within rcu_locks in ip_output.This will ensure that
all the skb's associated with the dev being deregistered will
be transnmitted out first, before freeing the dev.

Given that ip_output() is called within an rcu_read_lock()
critical section or from a bottom-half context, it is safe to introduce
an RCU read-side critical section within it.

Multiple panic call stacks were observed when UL traffic was run
in concurrency with device deregistration from different functions,
pasting one sample for reference.

[496733.627565][T13385] Call trace:
[496733.627570][T13385] bpf_prog_ce7c9180c3b128ea_cgroupskb_egres+0x24c/0x7f0
[496733.627581][T13385] __cgroup_bpf_run_filter_skb+0x128/0x498
[496733.627595][T13385] ip_finish_output+0xa4/0xf4
[496733.627605][T13385] ip_output+0x100/0x1a0
[496733.627613][T13385] ip_send_skb+0x68/0x100
[496733.627618][T13385] udp_send_skb+0x1c4/0x384
[496733.627625][T13385] udp_sendmsg+0x7b0/0x898
[496733.627631][T13385] inet_sendmsg+0x5c/0x7c
[496733.627639][T13385] __sys_sendto+0x174/0x1e4
[496733.627647][T13385] __arm64_sys_sendto+0x28/0x3c
[496733.627653][T13385] invoke_syscall+0x58/0x11c
[496733.627662][T13385] el0_svc_common+0x88/0xf4
[496733.627669][T13385] do_el0_svc+0x2c/0xb0
[496733.627676][T13385] el0_svc+0x2c/0xa4
[496733.627683][T13385] el0t_64_sync_handler+0x68/0xb4
[496733.627689][T13385] el0t_64_sync+0x1a4/0x1a8

Changes in v3:
- Replaced WARN_ON() with  WARN_ON_ONCE(), as suggested by Willem de Bruijn.
- Dropped legacy lines mistakenly pulled in from an outdated branch.

Changes in v2:
- Addressed review comments from Eric Dumazet
- Used READ_ONCE() to prevent potential load/store tearing
- Added skb_dst_dev_rcu() and used along with rcu_read_lock() in ip_output

Signed-off-by: Sharath Chandra Vurukala <quic_sharathv@quicinc.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250730105118.GA26100@hu-sharathv-hyd.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-01 15:17:52 -07:00
Takamitsu Iwai
ae8508b25d net/sched: taprio: enforce minimum value for picos_per_byte
Syzbot reported a WARNING in taprio_get_start_time().

When link speed is 470,589 or greater, q->picos_per_byte becomes too
small, causing length_to_duration(q, ETH_ZLEN) to return zero.

This zero value leads to validation failures in fill_sched_entry() and
parse_taprio_schedule(), allowing arbitrary values to be assigned to
entry->interval and cycle_time. As a result, sched->cycle can become zero.

Since SPEED_800000 is the largest defined speed in
include/uapi/linux/ethtool.h, this issue can occur in realistic scenarios.

To ensure length_to_duration() returns a non-zero value for minimum-sized
Ethernet frames (ETH_ZLEN = 60), picos_per_byte must be at least 17
(60 * 17 > PSEC_PER_NSEC which is 1000).

This patch enforces a minimum value of 17 for picos_per_byte when the
calculated value would be lower, and adds a warning message to inform
users that scheduling accuracy may be affected at very high link speeds.

Fixes: fb66df20a7 ("net/sched: taprio: extend minimum interval restriction to entire cycle too")
Reported-by: syzbot+398e1ee4ca2cac05fddb@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=398e1ee4ca2cac05fddb
Signed-off-by: Takamitsu Iwai <takamitz@amazon.co.jp>
Link: https://patch.msgid.link/20250728173149.45585-1-takamitz@amazon.co.jp
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-01 15:15:28 -07:00