deferred_init_memmap_chunk() calls deferred_init_maxorder() to initialize
struct pages in MAX_ORDER_NR_PAGES because according to commit 0e56acae4b
("mm: initialize MAX_ORDER_NR_PAGES at a time instead of doing larger
sections") this provides better cache locality than initializing the memory
map in larger sections.
The looping through free memory ranges is quite cumbersome in the current
implementation as it is divided between deferred_init_memmap_chunk() and
deferred_init_maxorder(). Besides, the latter has two loops, one that
initializes struct pages and another one that frees them.
There is no need in two loops because it is safe to free pages in groups
smaller than MAX_ORDER_NR_PAGES. Even if lookup for a buddy page will
access a struct page ahead of the pages being initialized, that page is
guaranteed to be initialized either by memmap_init_reserved_pages() or by
init_unavailable_range().
Simplify the code by moving initialization and freeing of the pages into
deferred_init_memmap_chunk() and dropping deferred_init_maxorder().
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
deferred_init_memmap() loops over free memory ranges and creates a
padata_mt_job for every free range that intersects with the zone being
initialized.
padata_do_multithreaded() then splits every such range to several chunks
and runs a thread that initializes struct pages in that chunk using
deferred_init_memmap_chunk(). The number of threads is limited by amount of
the CPUs on the node (or 1 for memoryless nodes).
Looping through free memory ranges is then repeated in
deferred_init_memmap_chunk() first to find the first range that should be
initialized and then to traverse the ranges until the end of the chunk is
reached.
Remove the loop over free memory regions in deferred_init_memmap() and pass
the entire zone to padata_do_multithreaded() so that it will be divided to
several chunks by the parallelization code.
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
deferred_grow_zone() initializes one or more sections in the memory map
if buddy runs out of initialized struct pages when
CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled.
It loops through memblock regions and initializes and frees pages in
MAX_ORDER_NR_PAGES chunks.
Essentially the same loop is implemented in deferred_init_memmap_chunk(),
the only actual difference is that deferred_init_memmap_chunk() does not
count initialized pages.
Make deferred_init_memmap_chunk() count the initialized pages and return
their number, wrap it with deferred_init_memmap_job() for multithreaded
initialization with padata_do_multithreaded() and replace open-coded
initialization of struct pages in deferred_grow_zone() with a call to
deferred_init_memmap_chunk().
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
The `cros_ec_keyb` driver can be probed before the cros_ec_device has
completed the registration. This creates a race condition where
`cros_ec_keyb` might access uninitialized data.
Fix this by calling `cros_ec_device_registered()` to check the parent's
status. If the device is not yet ready, return -EPROBE_DEFER to ensure
the probe is retried later.
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://lore.kernel.org/r/20250828083601.856083-6-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Introduce a `registered` flag to the `struct cros_ec_device` to allow
callers to determine if the device has been fully registered and is
ready for use.
This is a preparatory step to prevent race conditions where other drivers
might try to access the device before it is fully registered or after
it has been unregistered.
Link: https://lore.kernel.org/r/20250828083601.856083-5-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Move the initialization of the `struct cros_ec_device` from
cros_ec_register() into cros_ec_device_alloc().
This decouples device initialization from registration. By doing so,
the per-device lock is now available immediately after allocation,
allowing it to be used safely even before the device is fully
registered.
Link: https://lore.kernel.org/r/20250828083601.856083-4-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Move the common initialization from protocol device drivers into central
cros_ec_device_alloc().
This removes duplicated code from each driver's probe function.
The buffer sizes are now calculated once, using the maximum possible
overhead required by any of the transport protocols, ensuring the
allocated buffers are sufficient for all cases.
Link: https://lore.kernel.org/r/20250828083601.856083-3-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Introduce a helper function, cros_ec_device_alloc(), to centralize the
allocation of the struct cros_ec_device. Convert all protocol device
drivers to use this new function.
This is a preparatory step for separating common initialization logic
out of device drivers' probe() and cros_ec_register().
Link: https://lore.kernel.org/r/20250828083601.856083-2-tzungbi@kernel.org
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Emails to the sole melfas-mip4 driver maintainer bounce:
550 <jeesw@melfas.com> No such user here (connected from melfas.com)
so clearly this is not a supported driver anymore.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250910142526.105286-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
When KHO (Kexec HandOver) is enabled, it sets up scratch memory regions
early during device tree scanning. After kexec, the new kernel
exclusively uses this region for memory allocations during boot up to the
initialization of the page allocator
However, when booting with EFI, EFI's reserve_regions() uses
memblock_remove(0, PHYS_ADDR_MAX) to clear all memory regions before
rebuilding them from EFI data. This destroys KHO scratch regions and
their flags, thus causing a kernel panic, as there are no scratch memory
regions.
Instead of wholesale removal, iterate through memory regions and only
remove non-KHO ones. This preserves KHO scratch regions, which are good
known memory, while still allowing EFI to rebuild its memory map.
Link: https://lkml.kernel.org/r/b34da9fd50c89644cd4204136cfa6f5533445c56.1755721529.git.epetron@amazon.de
Signed-off-by: Evangelos Petrongonas <epetron@amazon.de>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "efi: Fix EFI boot with kexec handover (KHO)", v3.
This patch series fixes a kernel panic that occurs when booting with both
EFI and KHO (Kexec HandOver) enabled.
The issue arises because EFI's `reserve_regions()` clears all memory
regions with `memblock_remove(0, PHYS_ADDR_MAX)` before rebuilding them
from EFI data. This destroys KHO scratch regions that were set up early
during device tree scanning, causing a panic as the kernel has no valid
memory regions for early allocations.
The first patch introduces `is_kho_boot()` to allow early boot components
to reliably detect if the kernel was booted via KHO-enabled kexec. The
existing `kho_is_enabled()` only checks the command line and doesn't
verify if an actual KHO FDT was passed.
The second patch modifies EFI's `reserve_regions()` to selectively remove
only non-KHO memory regions when KHO is active, preserving the critical
scratch regions while still allowing EFI to rebuild its memory map.
This patch (of 3):
During early initialisation, after a kexec, other components, like EFI
need to know if a KHO enabled kexec is performed. The `kho_is_enabled`
function is not enough as in the early stages, it only reflects whether
the cmdline has KHO enabled, not if an actual KHO FDT exists.
Extend the KHO API with `is_kho_boot()` to provide a way for components to
check if a KHO enabled kexec is performed.
Link: https://lkml.kernel.org/r/cover.1755721529.git.epetron@amazon.de
Link: https://lkml.kernel.org/r/7dc6674a76bf6e68cca0222ccff32427699cc02e.1755721529.git.epetron@amazon.de
Signed-off-by: Evangelos Petrongonas <epetron@amazon.de>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit updates the delaytop documentation to reflect the newly
added features:
1) Added comprehensive description of interactive keyboard controls
2) Documented all available sort fields
3) Added examples for advanced usage scenarios
4) Included PSI availability note
Link: https://lkml.kernel.org/r/20250907001457696qAqUGGkV1VfEO6OkVMovW@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Enhanced display logic to conditionally show PSI information only when
successfully read, with helpful guidance for users to enable PSI support
(psi=1 cmdline parameter).
Link: https://lkml.kernel.org/r/20250907001417537vSx6nUsb3ILqI0iQ-WnGp@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The original delaytop only supported static output with limited
interaction. Users had to restart the tool with different command-line
options to change sorting or display modes, which disrupted continuous
monitoring and reduced productivity during performance investigations.
Adds real-time interactive controls through keyboard input:
1) Add interactive menu system with visual prompts
2) Support dynamic sorting changes without restarting
3) Enable toggle of memory verbose mode with 'M' key
The interactive mode transforms delaytop from a static monitoring tool
into a dynamic investigation platform, allowing users to adapt the view in
real-time based on observed performance patterns.
Link: https://lkml.kernel.org/r/20250907001338580EURha20BxWFmBSrUpS8D1@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The original delaytop tool always displayed detailed memory subsystem
breakdown, which could be overwhelming for users who only need high-level
overview.
Add flexible display control allowing users to choose their preferred
information granularity.
The new flexibility provides:
1) For quick monitoring: use normal mode to reduce visual clutter
2) For deep analysis: use verbose mode to see all memory subsystem details
Link: https://lkml.kernel.org/r/202509070012527934u0ySb3teQ4gOYKnocyNO@zte.com.cn
Signed-off-by: Fan Yu <fan.yu9@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Provide some basic comments about the system_states and what they imply.
Also convert the comments to kernel-doc format.
Split the enum declaration from the definition of the system_state
variable so that kernel-doc notation works cleanly with it. This is
picked up by Documentation/driver-api/basics.rst so it does not need
further inclusion in the kernel docbooks.
Link: https://lkml.kernel.org/r/20250907043857.2941203-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org> # v1
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> [v5]
Cc: "Brown, Len" <len.brown@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: James Bottomley <james.bottomley@HansenPartnership.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
crash_exclude_mem_range seems to be a simple function but there have been
multiple attempts to fix it,
- commit a2e9a95d21 ("kexec: Improve & fix crash_exclude_mem_range()
to handle overlapping ranges")
- commit 6dff315972 ("crash_core: fix and simplify the logic of
crash_exclude_mem_range()")
So add a set of unit tests to verify the correctness of current
implementation. Shall we change the function in the future, the unit
tests can also help prevent any regression. For example, we may make the
function smarter by allocating extra crash_mem range on demand thus there
is no need for the caller to foresee any memory range split or address
-ENOMEM failure.
The testing strategy is to verify the correctness of base case. The
base case is there is one to-be-excluded range A and one existing range
B. Then we can exhaust all possibilities of the position of A regarding
B. For example, here are two combinations,
Case: A is completely inside B (causes split)
Original: [----B----]
Exclude: {--A--}
Result: [B1] .. [B2]
Case: A overlaps B's left part
Original: [----B----]
Exclude: {---A---}
Result: [..B..]
In theory we can prove the correctness by induction,
- Base case: crash_exclude_mem_range is correct in the case where n=1
(n is the number of existing ranges).
- Inductive step: If crash_exclude_mem_range is correct for n=k
existing ranges, then the it's also correct for n=k+1 ranges.
But for the sake of simplicity, simply use unit tests to cover the base
case together with two regression tests.
Note most of the exclude_single_range_test() code is generated by Google
Gemini with some small tweaks. The function specification, function body
and the exhausting test strategy are presented as prompts.
[akpm@linux-foundation.org: export crash_exclude_mem_range() to modules, for kernel/crash_core_test.c]
Link: https://lkml.kernel.org/r/20250904093855.1180154-2-coxu@redhat.com
Signed-off-by: Coiby Xu <coxu@redhat.com>
Assisted-by: Google Gemini
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Dave Young <dyoung@redhat.com>
Cc: fuqiang wang <fuqiang.wang@easystack.cn>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In memmap_exclude_ranges(), elfheader will be excluded from crashk_res.
In the current x86 architecture code, the elfheader is always allocated at
crashk_res.start. It seems that there won't be a new split range. But it
depends on the allocation position of elfheader in crashk_res. To avoid
potential out of memory in future, add a extra slot. Otherwise loading
the kdump kernel will fail because crash_exclude_mem_range will return
-ENOMEM. random kexec_buf for passing dm crypt keys may cause a range
split too, add another extra slot here.
The similar issue also exists in fill_up_crash_elf_data(). The range to
be excluded is [0, 1M], start (0) is special and will not appear in the
middle of existing cmem->ranges[]. But in cast the low 1M could be
changed in the future, add a extra slot too.
Previous discussions:
[1] https://lore.kernel.org/kexec/ZXk2oBf%2FT1Ul6o0c@MiWiFi-R3L-srv/
[2] https://lore.kernel.org/kexec/273284e8-7680-4f5f-8065-c5d780987e59@easystack.cn/
[3] https://lore.kernel.org/kexec/ZYQ6O%2F57sHAPxTHm@MiWiFi-R3L-srv/
Link: https://lkml.kernel.org/r/20250904093855.1180154-1-coxu@redhat.com
Signed-off-by: fuqiang wang <fuqiang.wang@easystack.cn>
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Borislav Betkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Backtraces from all CPUs are printed during panic() when
SYS_INFO_ALL_CPU_BT is set. It shows the backtrace for the panic-CPU even
when it has already been explicitly printed before.
Do not change the legacy code which prints the backtrace in various
contexts, for example, as part of Oops report, right after panic message.
It will always be visible in the crash dump.
Instead, remember when the backtrace was printed, and skip it when dumping
the optional backtraces on all CPUs.
[akpm@linux-foundation.org: make panic_this_cpu_backtrace_printed static]
Closes: https://lore.kernel.org/oe-kbuild-all/202509050048.FMpVvh1u-lkp@intel.com/
[pmladek@suse.com: Handle situations when the backtrace was not printed for the panic CPU]
Link: https://lkml.kernel.org/r/20250903100418.410026-1-pmladek@suse.com
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Link: https://lore.kernel.org/r/20250731030314.3818040-1-senozhatsky@chromium.org
Signed-off-by: Petr Mladek <pmladek@suse.com>
Tested-by: Feng Tang <feng.tang@linux.alibaba.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace quoted includes of panic.h with `#include <linux/panic.h>` for
consistency across the kernel.
Link: https://lkml.kernel.org/r/20250829051312.33773-1-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The str_vsyscall_* constants in proc-pid-vm.c triggers
-Wunused-const-variable warnings with gcc-13.32 and clang 18.1.
Define and apply __maybe_unused locally to suppress the warnings. No
functional change
Fixes compiler warning:
warning: `str_vsyscall_*' defined but not used[-Wunused-const-variable]
Link: https://lkml.kernel.org/r/20250820175610.83014-1-reddybalavignesh9979@gmail.com
Signed-off-by: Bala-Vignesh-Reddy <reddybalavignesh9979@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Previously btree_merge() called btree_last() only to test existence, then
performed an extra btree_lookup() to fetch the value. This patch changes
it to directly use the value returned by btree_last(), avoiding redundant
lookups and simplifying the merge loop.
Link: https://lkml.kernel.org/r/20250826161741.686704-1-409411716@gms.tku.edu.tw
Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw>
Cc: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This issue was found when an EFI pstore was configured for kdump logging
with the NMI hard lockup detector enabled. The efi-pstore write operation
was slow, and with a large number of logs, the pstore dump callback within
kmsg_dump() took a long time.
This delay triggered the NMI watchdog, leading to a nested panic. The
call flow demonstrates how the secondary panic caused an
emergency_restart() to be triggered before the initial pstore operation
could finish, leading to a failure to dump the logs:
real panic() {
kmsg_dump() {
...
pstore_dump() {
start_dump();
... // long time operation triggers NMI watchdog
nmi panic() {
...
emergency_restart(); // pstore unfinished
}
...
finish_dump(); // never reached
}
}
}
Both watchdog_buddy_check_hardlockup() and watchdog_overflow_callback()
may trigger during a panic. This can lead to recursive panic handling.
Add panic_in_progress() checks so watchdog activity is skipped once a
panic has begun.
This prevents recursive panic and keeps the panic path more reliable.
Link: https://lkml.kernel.org/r/20250825022947.1596226-10-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Reviewed-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The helper this_cpu_in_panic() duplicated logic already provided by
panic_on_this_cpu().
Remove this_cpu_in_panic() and switch all users to panic_on_this_cpu().
This simplifies the code and avoids having two helpers for the same check.
Link: https://lkml.kernel.org/r/20250825022947.1596226-8-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nbcon_context_try_acquire() compared panic_cpu directly with
smp_processor_id(). This open-coded check is now provided by
panic_on_this_cpu().
Switch to panic_on_this_cpu() to simplify the code and improve readability.
Link: https://lkml.kernel.org/r/20250825022947.1596226-7-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
vpanic() had open-coded logic to claim panic_cpu with atomic_try_cmpxchg.
This is already handled by panic_try_start().
Switch to panic_try_start() and use panic_on_other_cpu() for the fallback
path.
This removes duplicate code and makes panic handling consistent across
functions.
Link: https://lkml.kernel.org/r/20250825022947.1596226-6-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
nmi_panic() duplicated the logic to claim panic_cpu with
atomic_try_cmpxchg. This is already wrapped in panic_try_start().
Replace the open-coded logic with panic_try_start(), and use
panic_on_other_cpu() for the fallback path.
This removes duplication and keeps panic handling code consistent.
Link: https://lkml.kernel.org/r/20250825022947.1596226-5-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
crash_kexec() had its own code to exclude parallel execution by setting
panic_cpu. This is already handled by panic_try_start(). Switch to
panic_try_start() to remove the duplication and keep the logic consistent.
Link: https://lkml.kernel.org/r/20250825022947.1596226-4-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Update the fbcon_skip_panic() function to use the panic_in_progress()
helper.
The previous direct access to panic_cpu is less readable and is being
replaced by a dedicated function that more clearly expresses the intent.
This change is part of a series to refactor the kernel's panic handling
logic for better clarity and robustness.
Link: https://lkml.kernel.org/r/20250825022947.1596226-3-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Acked-by Qianqiang Liu <qianqiang.liu@163.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "panic: introduce panic status function family", v2.
This series introduces a family of helper functions to manage panic state
and updates existing code to use them.
Before this series, panic state helpers were scattered and inconsistent.
For example, panic_in_progress() was defined in printk/printk.c, not in
panic.c or panic.h. As a result, developers had to look in unexpected
places to understand or re-use panic state logic. Other checks were open-
coded, duplicating logic across panic, crash, and watchdog paths.
The new helpers centralize the functionality in panic.c/panic.h:
- panic_try_start()
- panic_reset()
- panic_in_progress()
- panic_on_this_cpu()
- panic_on_other_cpu()
Patches 1–8 add the helpers and convert panic/crash and printk/nbcon
code to use them.
Patch 9 fixes a bug in the watchdog subsystem by skipping checks when a
panic is in progress, avoiding interference with the panic CPU.
Together, this makes panic state handling simpler, more discoverable, and
more robust.
This patch (of 9):
This patch introduces four new helper functions to abstract the management
of the panic_cpu variable. These functions will be used in subsequent
patches to refactor existing code.
The direct use of panic_cpu can be error-prone and ambiguous, as it
requires manual checks to determine which CPU is handling the panic. The
new helpers clarify intent:
panic_try_start():
Atomically sets the current CPU as the panicking CPU.
panic_reset():
Reset panic_cpu to PANIC_CPU_INVALID.
panic_in_progress():
Checks if a panic has been triggered.
panic_on_this_cpu():
Returns true if the current CPU is the panic originator.
panic_on_other_cpu():
Returns true if a panic is on another CPU.
This change lays the groundwork for improved code readability
and robustness in the panic handling subsystem.
Link: https://lkml.kernel.org/r/20250825022947.1596226-1-wangjinchao600@gmail.com
Link: https://lkml.kernel.org/r/20250825022947.1596226-2-wangjinchao600@gmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@gmail.com>
Cc: Anna Schumaker <anna.schumaker@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com>
Cc: Joel Granados <joel.granados@kernel.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Kees Cook <kees@kernel.org>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Luo Gengkun <luogengkun@huaweicloud.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Nam Cao <namcao@linutronix.de>
Cc: oushixiong <oushixiong@kylinos.cn>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Qianqiang Liu <qianqiang.liu@163.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: Yury Norov (NVIDIA) <yury.norov@gmail.com>b
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove duplication of the message about deprecated 'panic_print'
parameter.
Also make the wording more direct. Make it clear that the new parameters
already exist and should be used instead.
Link: https://lkml.kernel.org/r/20250825025701.81921-5-feng.tang@linux.alibaba.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Tested-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Feng Tang <feng.tang@linux.alibaba.com>
Cc: Askar Safin <safinaskar@zohomail.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Just like for 'panic_print's systcl interface, add similar note for setup
of kernel cmdline parameter and parameter under /sys/module/kernel/.
Also add __core_param_cb() macro, which enables to add special get/set
operation for a kernel parameter.
Link: https://lkml.kernel.org/r/20250825025701.81921-4-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Askar Safin <safinaskar@zohomail.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
User reported current document about SYS_INFO_PANIC_CONSOLE_REPLAY is
confusing, that people could expect all user space console messages to be
replayed.
Specify that only 'kernel' messages will be replayed to solve the confusion.
Link: https://lkml.kernel.org/r/20250825025701.81921-3-feng.tang@linux.alibaba.com
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Reported-by: Askar Safin <safinaskar@zohomail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Generalization of panic_print's dump function [1] has been merged, and
this patchset is to address some remaining issues, like adding note of the
obsoletion of 'panic_print' cmdline parameter, refining the kernel
document for panic_print, and hardening some string management.
This patch (of 4):
It is a normal case that bitmask parameter is 0, so pre-initialize the
names[] to null string to cover this case.
Also remove the superfluous "+1" in names[sizeof(sys_info_avail) + 1],
which is needed for 'strlen()', but not for 'sizeof()'.
Link: https://lkml.kernel.org/r/20250825025701.81921-1-feng.tang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20250825025701.81921-2-feng.tang@linux.alibaba.com
Link: Link: https://lkml.kernel.org/r/20250703021004.42328-1-feng.tang@linux.alibaba.com [1]
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Askar Safin <safinaskar@zohomail.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The kimage struct is already zeroed by kzalloc(). It's redundant to
initialize image->head to 0.
Link: https://lkml.kernel.org/r/20250825123307.306634-1-liaoyuanhong@vivo.com
Signed-off-by: Liao Yuanhong <liaoyuanhong@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The offset annotation for s_reserved2 in struct ocfs2_super_block
was incorrect. After the preceding fields:
- s_xattr_inline_size (2 bytes at 0xB8)
- s_reserved0 (2 bytes at 0xBA)
- s_dx_seed[3] (12 bytes at 0xBC)
The actual offset of s_reserved2 is at 0xC8, when calculating from the
start of the structure.
Correct the offset comment from C0 to C8 to reflect the proper location in
the super block structure.
Link: https://lkml.kernel.org/r/20250807155749.164481-1-yili@winhong.com
Signed-off-by: yili <yili@winhong.com>
Reviewed-by: Joel Becker <jlbec@evilplan.org>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Smatch complains that checking "folios" for NULL doesn't make sense
because it has already been dereferenced at this point. Really passing a
NULL "folios" pointer to ocfs2_grab_folios() doesn't make sense, and
fortunately none of the callers do that. Delete the unnecessary NULL
check.
Link: https://lkml.kernel.org/r/aKRG39hyvDJcN2G7@stanley.mountain
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Mark Tinguely <mark.tinguely@oracle.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Unlike sys_clone(), these helpers have only in kernel users which should
pass the correct "flags" argument. lower_32_bits(flags) just adds the
unnecessary confusion and doesn't allow to use the CLONE_ flags which
don't fit into 32 bits.
create_io_thread() looks especially confusing because:
- "flags" is a compile-time constant, so lower_32_bits() simply
has no effect
- .exit_signal = (lower_32_bits(flags) & CSIGNAL) is harmless but
doesn't look right, copy_process(CLONE_THREAD) will ignore this
argument anyway.
None of these helpers actually need CLONE_UNTRACED or "& ~CSIGNAL", but
their presence does not add any confusion and improves code clarity.
Link: https://lkml.kernel.org/r/20250820163946.GA18549@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
lockdep_init_task() is defined as an empty when CONFIG_LOCKDEP is not set.
So the #ifdef here is redundant, remove it.
Link: https://lkml.kernel.org/r/20250820101826.GA2484@didi-ThinkCentre-M930t-N000
Signed-off-by: Tio Zhang <tiozhang@didiglobal.com>
Cc: Kees Cook <kees@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kernel-doc for the basic LIST_HEAD() and LIST_HEAD_INIT() macros has been
missing forever (i.e., since git). Add them for completeness.
Link: https://lkml.kernel.org/r/20250819075507.113639-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This line in tools/testing/selftests/proc/read.c was added to catch
oopses, not to verify lseek correctness:
(void)lseek(fd, 0, SEEK_SET);
Oh, well. Prevent more embarassement with simple test.
Link: https://lkml.kernel.org/r/aKTCfMuRXOpjBXxI@p183
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Remove unused variable definition and related function definition and
redundant variable assignments within functions.
Link: https://lkml.kernel.org/r/tencent_9DE7CC9367096503F6ADD2BD960079267406@qq.com
Signed-off-by: zhoumin <teczm@foxmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since we use 16-bit precision, the raw data will undergo integer division,
which may sometimes result in data loss. This can lead to slightly
inaccurate CPU utilization calculations. Under normal circumstances, this
isn't an issue. However, when CPU utilization reaches 100%, the
calculated result might exceed 100%. For example, with raw data like the
following:
sample_period 400000134 new_stat 83648414036 old_stat 83247417494
sample_period=400000134/2^24=23
new_stat=83648414036/2^24=4985
old_stat=83247417494/2^24=4961
util=105%
Below log will output：
CPU#3 Utilization every 0s during lockup:
#1: 0% system, 0% softirq, 105% hardirq, 0% idle
#2: 0% system, 0% softirq, 105% hardirq, 0% idle
#3: 0% system, 0% softirq, 100% hardirq, 0% idle
#4: 0% system, 0% softirq, 105% hardirq, 0% idle
#5: 0% system, 0% softirq, 105% hardirq, 0% idle
To avoid confusion, we enforce a 100% display cap when calculations exceed
this threshold.
We also round to the nearest multiple of 16.8 milliseconds to improve the
accuracy.
[yaozhenguo1@gmail.com: make get_16bit_precision() more accurate, fix comment layout]
Link: https://lkml.kernel.org/r/20250818081438.40540-1-yaozhenguo@jd.com
Link: https://lkml.kernel.org/r/20250812082510.32291-1-yaozhenguo@jd.com
Signed-off-by: ZhenguoYao <yaozhenguo1@gmail.com>
Cc: Bitao Hu <yaoma@linux.alibaba.com>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When watchdog_thresh is below 3, sample_period will be less than 1 second.
So the following output will print when softlockup:
CPU#3 Utilization every 0s during lockup
Fix this by changing time unit from seconds to milliseconds.
Link: https://lkml.kernel.org/r/20250812074132.27810-1-yaozhenguo@jd.com
Signed-off-by: ZhenguoYao <yaozhenguo1@gmail.com>
Cc: Bitao Hu <yaoma@linux.alibaba.com>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: Max Kellermann <max.kellermann@ionos.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace the ternary (enable ? "on" : "off") with the str_on_off() helper
from string_choices.h. This improves readability by replacing the
three-operand ternary with a single function call, ensures consistent
string output, and allows potential string deduplication by the linker,
resulting in a slightly smaller binary.
Link: https://lkml.kernel.org/r/20250814093827.237980-1-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
