As part of the dynamic kernel stack project, we need to know the amount of
data that can be saved by reducing the default kernel stack size [1].
Provide a kernel stack usage histogram to aid in optimizing kernel stack
sizes and minimizing memory waste in large-scale environments. The
histogram divides stack usage into power-of-two buckets and reports the
results in /proc/vmstat. This information is especially valuable in
environments with millions of machines, where even small optimizations can
have a significant impact.
The histogram data is presented in /proc/vmstat with entries like
"kstack_1k", "kstack_2k", and so on, indicating the number of threads that
exited with stack usage falling within each respective bucket.
Example outputs:
Intel:
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
ARM with 64K page_size:
$ grep kstack /proc/vmstat
kstack_1k 1
kstack_2k 340
kstack_4k 25212
kstack_8k 1659
kstack_16k 0
kstack_32k 0
kstack_64k 0
Note: once the dynamic kernel stack is implemented it will depend on the
implementation the usability of this feature: On hardware that supports
faults on kernel stacks, we will have other metrics that show the total
number of pages allocated for stacks. On hardware where faults are not
supported, we will most likely have some optimization where only some
threads are extended, and for those, these metrics will still be very
useful.
[1] https://lwn.net/Articles/974367
Link: https://lkml.kernel.org/r/20240730150158.832783-3-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240724203322.2765486-3-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Kernel stack usage histogram", v6.
Provide histogram of stack sizes for the exited threads:
Example outputs:
Intel:
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
ARM with 64K page_size:
$ grep kstack /proc/vmstat
kstack_1k 1
kstack_2k 340
kstack_4k 25212
kstack_8k 1659
kstack_16k 0
kstack_32k 0
kstack_64k 0
This patch (of 3):
At the moment the valid index for the indirection tables for memcg stats
and events is < S8_MAX. These indirection tables are used in performance
critical codepaths. With the latest addition to the vm_events, the
NR_VM_EVENT_ITEMS has gone over S8_MAX. One way to resolve is to increase
the entry size of the indirection table from int8_t to int16_t but this
will increase the potential number of cachelines needed to access the
indirection table.
This patch took a different approach and make the valid index < U8_MAX.
In this way the size of the indirection tables will remain same and we
only need to invalid index check from less than 0 to equal to U8_MAX. In
this approach we have also removed a subtraction from the performance
critical codepaths.
[pasha.tatashin@soleen.com: v6]
Link: https://lkml.kernel.org/r/20240730150158.832783-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240724203322.2765486-1-pasha.tatashin@soleen.com
Link: https://lkml.kernel.org/r/20240724203322.2765486-2-pasha.tatashin@soleen.com
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The releasing process of the non-shared anonymous folio mapped solely by
an exiting process may go through two flows: 1) the anonymous folio is
firstly is swaped-out into swapspace and transformed into a swp_entry in
shrink_folio_list; 2) then the swp_entry is released in the process
exiting flow. This will result in the high cpu load of releasing a
non-shared anonymous folio mapped solely by an exiting process.
When the low system memory and the exiting process exist at the same time,
it will be likely to happen, because the non-shared anonymous folio mapped
solely by an exiting process may be reclaimed by shrink_folio_list.
This patch is that shrink skips the non-shared anonymous folio solely
mapped by an exting process and this folio is only released directly in
the process exiting flow, which will save swap-out time and alleviate the
load of the process exiting.
Barry provided some effectiveness testing in [1]. "I observed that
this patch effectively skipped 6114 folios (either 4KB or 64KB mTHP),
potentially reducing the swap-out by up to 92MB (97,300,480 bytes)
during the process exit. The working set size is 256MB."
Link: https://lkml.kernel.org/r/20240710083641.546-1-justinjiang@vivo.com
Link: https://lore.kernel.org/linux-mm/20240710033212.36497-1-21cnbao@gmail.com/ [1]
Signed-off-by: Zhiguo Jiang <justinjiang@vivo.com>
Acked-by: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fold lru_rotate into cpu_fbatches, and rename the folio_batch and the lock
protecting it to lru_move_tail and lock_irq respectively so that all the
boilerplate can be removed at the end of this series.
Also remove data_race() around folio_batch_count(), which is out of place:
all folio_batch_count() calls on remote cpu_fbatches are subject to
data_race(), and therefore data_race() should be inside
folio_batch_count().
Link: https://lkml.kernel.org/r/20240711021317.596178-4-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename cpu_fbatches->activate to cpu_fbatches->lru_activate, and its
handler folio_activate_fn() to lru_activate() so that all the boilerplate
can be removed at the end of this series.
Link: https://lkml.kernel.org/r/20240711021317.596178-3-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/swap: remove boilerplate".
This patch (of 5):
Use folio_activate() as an example:
Before this series
------------------
if (!folio_test_active(folio) && !folio_test_unevictable(folio)) {
struct folio_batch *fbatch;
folio_get(folio);
if (!folio_test_clear_lru(folio)) {
folio_put(folio);
return;
}
local_lock(&cpu_fbatches.lock);
fbatch = this_cpu_ptr(&cpu_fbatches.activate);
folio_batch_add_and_move(fbatch, folio, folio_activate_fn);
local_unlock(&cpu_fbatches.lock);
}
}
After this series
-----------------
void folio_activate(struct folio *folio)
{
if (folio_test_active(folio) || folio_test_unevictable(folio))
return;
folio_batch_add_and_move(folio, lru_activate, true);
}
And this is applied to all 6 folio_batch handlers in mm/swap.c.
bloat-o-meter
-------------
add/remove: 12/13 grow/shrink: 3/2 up/down: 4653/-4721 (-68)
...
Total: Before=28083019, After=28082951, chg -0.00%
This patch (of 5):
Reduce indentation level by returning directly when there is no cleanup
needed, i.e.,
if (condition) { | if (condition) {
do_this(); | do_this();
return; | return;
} else { | }
do_that(); |
} | do_that();
and
if (condition) { | if (!condition)
do_this(); | return;
do_that(); |
} | do_this();
return; | do_that();
Presumably the old style became repetitive as the result of copy and
paste.
Link: https://lkml.kernel.org/r/20240711021317.596178-1-yuzhao@google.com
Link: https://lkml.kernel.org/r/20240711021317.596178-2-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
memory tiering can be enabled/disabled at runtime and
sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING is used to
check it. In migrate_misplaced_folio(), the check is missing when
PGPROMOTE_SUCCESS is incremented. Add the missing check.
Link: https://lkml.kernel.org/r/20240724130115.793641-4-ziy@nvidia.com
Fixes: 33024536ba ("memory tiering: hot page selection with hint page fault latency")
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Closes: https://lore.kernel.org/linux-mm/f4ae2c9c-fe40-4807-bdb2-64cf2d716c1a@huawei.com/
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If memory tiering mode is on and a folio is not in the top tier memory,
folio's cpupid field is repurposed to store page access time. Instead of
an open coded check, use a function to encapsulate the check.
Link: https://lkml.kernel.org/r/20240724130115.793641-3-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Various memory tiering fixes", v3.
This patch (of 3):
last_cpupid is only available when memory tiering is off or the folio is
in toptier node. Complete the check to read last_cpupid when it is
available.
Before the fix, the default last_cpupid will be used even if memory
tiering mode is turned off at runtime instead of the actual value. This
can prevent task_numa_fault() from getting right numa fault stats, but
should not cause any crash. User might see performance changes after the
fix.
Link: https://lkml.kernel.org/r/20240724130115.793641-1-ziy@nvidia.com
Link: https://lkml.kernel.org/r/20240724130115.793641-2-ziy@nvidia.com
Fixes: 33024536ba ("memory tiering: hot page selection with hint page fault latency")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: David Hildenbrand <david@redhat.com>
Closes: https://lore.kernel.org/linux-mm/9af34a6b-ca56-4a64-8aa6-ade65f109288@redhat.com/
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Extend a usage parameter so that cluster_swap_free_nr() can be reused by
both swapcache_clear() and swap_free(). __swap_entry_free() is quite
similar but more tricky as it requires the return value of
__swap_entry_free_locked() which cluster_swap_free_nr() doesn't support.
Link: https://lkml.kernel.org/r/20240724020056.65838-1-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no user of mem_cgroup_from_obj(), remove it.
Link: https://lkml.kernel.org/r/20240718091821.44740-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now that we're not passing around a pointer to the flags, there's no
reason to have an extra variable for the gup_flags, simply pass the
gup_flags directly everywhere.
Link: https://lkml.kernel.org/r/1e79b84bd30287cc9847f2aeb002374e6e60a10f.1721337845.git.josef@toxicpanda.com
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: some small page fault cleanups".
I was recently wreaking havoc in the page fault code and I noticed some
things that could be cleaned up. We no longer modify the gup flags in
faultin_page, so we can clean up how we pass the flags in and remove the
extra variable in __get_user_pages.
This patch (of 2):
We're passing a pointer to the foll_flags for faultin_page, however we
never modify the flags in this call. Change this to just take the flags
value instead.
Link: https://lkml.kernel.org/r/2df51a54c06bdf93e1cb09a19a9ef1df6557b59e.1721337845.git.josef@toxicpanda.com
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When KASAN is enabled and built with clang:
mm/damon/lru_sort.c:199:12: error: stack frame size (2328) exceeds
limit (2048) in 'damon_lru_sort_apply_parameters' [-Werror,-Wframe-larger-than]
static int damon_lru_sort_apply_parameters(void)
^
1 error generated.
This is because damon_lru_sort_quota contains a large array, and
assigning this variable to a local variable causes a large amount of
stack space to be occupied.
So adjust local variable to dynamic allocation.
Link: https://lkml.kernel.org/r/20240723035513.20153-1-flyingpeng@tencent.com
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
hugetlb_vmemmap_optimize_folio() and hugetlb_vmemmap_restore_folio() are
wrappers meant to be called regardless of whether HVO is enabled.
Therefore, they should not call synchronize_rcu(). Otherwise, it
regresses use cases not enabling HVO.
So move synchronize_rcu() to __hugetlb_vmemmap_optimize_folio() and
__hugetlb_vmemmap_restore_folio(), and call it once for each batch of
folios when HVO is enabled.
Link: https://lkml.kernel.org/r/20240719042503.2752316-1-yuzhao@google.com
Fixes: bd225530a4 ("mm/hugetlb_vmemmap: fix race with speculative PFN walkers")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407091001.1250ad4a-oliver.sang@intel.com
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Initially I added shmem-quota to obj-y, move it to the correct place and
remove the unneeded full file #ifdef
Link: https://lkml.kernel.org/r/20240717063737.910840-1-cem@kernel.org
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Suggested-by: Aristeu Rozanski <aris@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fix typo in Kconfig help
Link: https://lkml.kernel.org/r/78656.1720853990@turing-police
Fixes: e93d4166b4 ("mm: memcg: put cgroup v1-specific code under a config option")
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move shmem_huge_global_enabled() into shmem_allowable_huge_orders(), so
that shmem_allowable_huge_orders() can also help to find the allowable
huge orders for tmpfs. Moreover the shmem_huge_global_enabled() can
become static. While we are at it, passing the vma instead of mm for
shmem_huge_global_enabled() makes code cleaner.
No functional changes.
Link: https://lkml.kernel.org/r/8e825146bb29ee1a1c7bd64d2968ff3e19be7815.1721626645.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
shmem_is_huge() is now used to check if the top-level huge page is
enabled, thus rename it to reflect its usage.
Link: https://lkml.kernel.org/r/da53296e0ab6359aa083561d9dc01e4223d60fbe.1721626645.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Some cleanups for shmem", v3.
This series does some cleanups to reuse code, rename functions and
simplify logic to make code more clear. No functional changes are
expected.
This patch (of 3):
Move the suitable huge orders validation into shmem_suitable_orders() for
tmpfs, which can reuse some code to simplify the logic.
In addition, we don't have special handling for the error code -E2BIG when
checking for conflicts with PMD sized THP in the pagecache for tmpfs,
instead, it will just fallback to order-0 allocations like this patch
does, so this simplification will not add functional changes.
Link: https://lkml.kernel.org/r/cover.1721626645.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/965985dd6d322929d78a0beee0dafa1c2a1b81e2.1721626645.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Barry Song <21cnbao@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Besides the obvious (and desired) difference between krealloc() and
kvrealloc(), there is some inconsistency in their function signatures and
behavior:
- krealloc() frees the memory when the requested size is zero, whereas
kvrealloc() simply returns a pointer to the existing allocation.
- krealloc() behaves like kmalloc() if a NULL pointer is passed, whereas
kvrealloc() does not accept a NULL pointer at all and, if passed,
would fault instead.
- krealloc() is self-contained, whereas kvrealloc() relies on the caller
to provide the size of the previous allocation.
Inconsistent behavior throughout allocation APIs is error prone, hence
make kvrealloc() behave like krealloc(), which seems superior in all
mentioned aspects.
Besides that, implementing kvrealloc() by making use of krealloc() and
vrealloc() provides oppertunities to grow (and shrink) allocations more
efficiently. For instance, vrealloc() can be optimized to allocate and
map additional pages to grow the allocation or unmap and free unused pages
to shrink the allocation.
[dakr@kernel.org: document concurrency restrictions]
Link: https://lkml.kernel.org/r/20240725125442.4957-1-dakr@kernel.org
[dakr@kernel.org: disable KASAN when switching to vmalloc]
Link: https://lkml.kernel.org/r/20240730185049.6244-2-dakr@kernel.org
[dakr@kernel.org: properly document __GFP_ZERO behavior]
Link: https://lkml.kernel.org/r/20240730185049.6244-5-dakr@kernel.org
Link: https://lkml.kernel.org/r/20240722163111.4766-3-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Align kvrealloc() with krealloc()", v2.
Besides the obvious (and desired) difference between krealloc() and
kvrealloc(), there is some inconsistency in their function signatures and
behavior:
- krealloc() frees the memory when the requested size is zero, whereas
kvrealloc() simply returns a pointer to the existing allocation.
- krealloc() behaves like kmalloc() if a NULL pointer is passed, whereas
kvrealloc() does not accept a NULL pointer at all and, if passed, would fault
instead.
- krealloc() is self-contained, whereas kvrealloc() relies on the caller to
provide the size of the previous allocation.
Inconsistent behavior throughout allocation APIs is error prone, hence
make kvrealloc() behave like krealloc(), which seems superior in all
mentioned aspects.
In order to be able to get rid of kvrealloc()'s oldsize parameter,
introduce vrealloc() and make use of it in kvrealloc().
Making use of vrealloc() in kvrealloc() also provides oppertunities to
grow (and shrink) allocations more efficiently. For instance, vrealloc()
can be optimized to allocate and map additional pages to grow the
allocation or unmap and free unused pages to shrink the allocation.
Besides the above, those functions are required by Rust's allocator abstractons
[1] (rework based on this series in [2]). With `Vec` or `KVec` respectively,
potentially growing (and shrinking) data structures are rather common.
[1] https://lore.kernel.org/lkml/20240704170738.3621-1-dakr@redhat.com/
[2] https://git.kernel.org/pub/scm/linux/kernel/git/dakr/linux.git/log/?h=rust/mm
This patch (of 2):
Implement vrealloc() analogous to krealloc().
Currently, krealloc() requires the caller to pass the size of the previous
memory allocation, which, instead, should be self-contained.
We attempt to fix this in a subsequent patch which, in order to do so,
requires vrealloc().
Besides that, we need realloc() functions for kernel allocators in Rust
too. With `Vec` or `KVec` respectively, potentially growing (and
shrinking) data structures are rather common.
[dakr@kernel.org: fix missing nommu implementation]
Link: https://lkml.kernel.org/r/20240725141227.13954-1-dakr@kernel.org
[dakr@kernel.org: document concurrency restrictions]
Link: https://lkml.kernel.org/r/20240725125442.4957-1-dakr@kernel.org
[dakr@kernel.org: consider spare memory for __GFP_ZERO]
Link: https://lkml.kernel.org/r/20240730185049.6244-3-dakr@kernel.org
[dakr@kernel.org: properly document __GFP_ZERO behavior]
Link: https://lkml.kernel.org/r/20240730185049.6244-4-dakr@kernel.org
Link: https://lkml.kernel.org/r/20240722163111.4766-1-dakr@kernel.org
Link: https://lkml.kernel.org/r/20240722163111.4766-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
/proc/vmstat currently shows the number of node_reclaim() failures when
vm.zone_reclaim_mode is set appropriately. It would be convenient to have
the number of successes right next to zone_reclaim_failed (similar to
compaction and migration).
While just a trivially addition to the vmstat file. It was helpful during
benchmarking to not have to probe node_reclaim() to observe the
success/failure ratio.
Link: https://lkml.kernel.org/r/20240722171316.7517-1-mcassell411@gmail.com
Signed-off-by: Matthew Cassell <mcassell411@gmail.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Li Zhijian <lizhijian@fujitsu.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
- Fix a potential memory leak in the ata host initialization code (from
Zheng).
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Merge tag 'ata-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux
Pull ata fix from Damien Le Moal:
- Fix a potential memory leak in the ata host initialization code (from
Zheng)
* tag 'ata-6.11-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux:
ata: libata: Fix memory leak for error path in ata_host_alloc()
The scan interval option is the period in unit of second for WoWLAN
firmware to do each scan. We get the option from cfg80211 and practice it.
If the interval is too short for firmware to finish one scan, the firmware
will start next scan immediately after finishing one and the WiFi chip
could never enter idle mode to reduce power consumption.
Signed-off-by: Chin-Yen Lee <timlee@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240826090439.17242-5-pkshih@realtek.com
The C2H packet of FW-IPS mode is not handled by driver in the suspend
flow, and lead to WoWLAN firmware fail to enter PS mode and even some
SER happen. So add wait function for H2C of FW-IPS mode to check driver
handle the C2H packet before disabling interrupt and make the net-detect
function work fine.
Signed-off-by: Chin-Yen Lee <timlee@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240826090439.17242-3-pkshih@realtek.com
Each condition binding to the same wait should be unique. AOAC code misused
the wait of FW offload series and broke the above rule. It added another
macro to generate wait condition of WoWLAN/AOAC, but the results conflict
to the ones of FW offload series. It means that we might be completed
wrongly in logic. We don't want things work/read like this and should
have avoided this.
Fix this by adding another wait which aims for WoWLAN functions.
Fixes: ff53fce5c7 ("wifi: rtw89: wow: update latest PTK GTK info to mac80211 after resume")
Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240826090439.17242-2-pkshih@realtek.com
codetag_module_init() is used to initialize sections containing allocation
tags. This function is used to initialize module sections as well as core
kernel sections, in which case the module parameter is set to NULL. This
function has to be called even when CONFIG_MODULES=n to initialize core
kernel allocation tag sections. When CONFIG_MODULES=n, this function is a
NOP, which is wrong. This leads to /proc/allocinfo reported as empty.
Fix this by making it independent of CONFIG_MODULES.
Link: https://lkml.kernel.org/r/20240828231536.1770519-1-surenb@google.com
Fixes: 916cc5167c ("lib: code tagging framework")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> [6.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When running the vmalloc stress on a 448-core system, observe the average
latency of purge_vmap_node() is about 2 seconds by using the eBPF/bcc
'funclatency.py' tool [1].
# /your-git-repo/bcc/tools/funclatency.py -u purge_vmap_node & pid1=$! && sleep 8 && modprobe test_vmalloc nr_threads=$(nproc) run_test_mask=0x7; kill -SIGINT $pid1
usecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 29 | |
4 -> 7 : 19 | |
8 -> 15 : 56 | |
16 -> 31 : 483 |**** |
32 -> 63 : 1548 |************ |
64 -> 127 : 2634 |********************* |
128 -> 255 : 2535 |********************* |
256 -> 511 : 1776 |************** |
512 -> 1023 : 1015 |******** |
1024 -> 2047 : 573 |**** |
2048 -> 4095 : 488 |**** |
4096 -> 8191 : 1091 |********* |
8192 -> 16383 : 3078 |************************* |
16384 -> 32767 : 4821 |****************************************|
32768 -> 65535 : 3318 |*************************** |
65536 -> 131071 : 1718 |************** |
131072 -> 262143 : 2220 |****************** |
262144 -> 524287 : 1147 |********* |
524288 -> 1048575 : 1179 |********* |
1048576 -> 2097151 : 822 |****** |
2097152 -> 4194303 : 906 |******* |
4194304 -> 8388607 : 2148 |***************** |
8388608 -> 16777215 : 4497 |************************************* |
16777216 -> 33554431 : 289 |** |
avg = 2041714 usecs, total: 78381401772 usecs, count: 38390
The worst case is over 16-33 seconds, so soft lockup is triggered [2].
[Root Cause]
1) Each purge_list has the long list. The following shows the number of
vmap_area is purged.
crash> p vmap_nodes
vmap_nodes = $27 = (struct vmap_node *) 0xff2de5a900100000
crash> vmap_node 0xff2de5a900100000 128 | grep nr_purged
nr_purged = 663070
...
nr_purged = 821670
nr_purged = 692214
nr_purged = 726808
...
2) atomic_long_sub() employs the 'lock' prefix to ensure the atomic
operation when purging each vmap_area. However, the iteration is over
600000 vmap_area (See 'nr_purged' above).
Here is objdump output:
$ objdump -D vmlinux
ffffffff813e8c80 <purge_vmap_node>:
...
ffffffff813e8d70: f0 48 29 2d 68 0c bb lock sub %rbp,0x2bb0c68(%rip)
...
Quote from "Instruction tables" pdf file [3]:
Instructions with a LOCK prefix have a long latency that depends on
cache organization and possibly RAM speed. If there are multiple
processors or cores or direct memory access (DMA) devices, then all
locked instructions will lock a cache line for exclusive access,
which may involve RAM access. A LOCK prefix typically costs more
than a hundred clock cycles, even on single-processor systems.
That's why the latency of purge_vmap_node() dramatically increases
on a many-core system: One core is busy on purging each vmap_area of
the *long* purge_list and executing atomic_long_sub() for each
vmap_area, while other cores free vmalloc allocations and execute
atomic_long_add_return() in free_vmap_area_noflush().
[Solution]
Employ a local variable to record the total purged pages, and execute
atomic_long_sub() after the traversal of the purge_list is done. The
experiment result shows the latency improvement is 99%.
[Experiment Result]
1) System Configuration: Three servers (with HT-enabled) are tested.
* 72-core server: 3rd Gen Intel Xeon Scalable Processor*1
* 192-core server: 5th Gen Intel Xeon Scalable Processor*2
* 448-core server: AMD Zen 4 Processor*2
2) Kernel Config
* CONFIG_KASAN is disabled
3) The data in column "w/o patch" and "w/ patch"
* Unit: micro seconds (us)
* Each data is the average of 3-time measurements
System w/o patch (us) w/ patch (us) Improvement (%)
--------------- -------------- ------------- -------------
72-core server 2194 14 99.36%
192-core server 143799 1139 99.21%
448-core server 1992122 6883 99.65%
[1] https://github.com/iovisor/bcc/blob/master/tools/funclatency.py
[2] https://gist.github.com/AdrianHuang/37c15f67b45407b83c2d32f918656c12
[3] https://www.agner.org/optimize/instruction_tables.pdf
Link: https://lkml.kernel.org/r/20240829130633.2184-1-ahuang12@lenovo.com
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Soon I won't be able to use my current email address.
Link: https://lkml.kernel.org/r/20240830095658.1203198-1-jankul@alatek.krakow.pl
Signed-off-by: Jan Kuliga <jankul@alatek.krakow.pl>
Cc: David S. Miller <davem@davemloft.net>
Cc: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, the behavior of zswap.writeback wrt. the cgroup hierarchy
seems a bit odd. Unlike zswap.max, it doesn't honor the value from parent
cgroups. This surfaced when people tried to globally disable zswap
writeback, i.e. reserve physical swap space only for hibernation [1] -
disabling zswap.writeback only for the root cgroup results in subcgroups
with zswap.writeback=1 still performing writeback.
The inconsistency became more noticeable after I introduced the
MemoryZSwapWriteback= systemd unit setting [2] for controlling the knob.
The patch assumed that the kernel would enforce the value of parent
cgroups. It could probably be workarounded from systemd's side, by going
up the slice unit tree and inheriting the value. Yet I think it's more
sensible to make it behave consistently with zswap.max and friends.
[1] https://wiki.archlinux.org/title/Power_management/Suspend_and_hibernate#Disable_zswap_writeback_to_use_the_swap_space_only_for_hibernation
[2] https://github.com/systemd/systemd/pull/31734
Link: https://lkml.kernel.org/r/20240823162506.12117-1-me@yhndnzj.com
Fixes: 501a06fe8e ("zswap: memcontrol: implement zswap writeback disabling")
Signed-off-by: Mike Yuan <me@yhndnzj.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Richard reports that since 772dd03427 ("mm: enumerate all gfp flags"),
gfp-translate is broken, as the bit numbers are implicit, leaving the
shell script unable to extract them. Even more, some bits are now at a
variable location, making it double extra hard to parse using a simple
shell script.
Use a brute-force approach to the problem by generating a small C stub
that will use the enum to dump the interesting bits.
As an added bonus, we are now able to identify invalid bits for a given
configuration. As an added drawback, we cannot parse include files that
predate this change anymore. Tough luck.
Link: https://lkml.kernel.org/r/20240823163850.3791201-1-maz@kernel.org
Fixes: 772dd03427 ("mm: enumerate all gfp flags")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reported-by: Richard Weinberger <richard@nod.at>
Cc: Petr Tesařík <petr@tesarici.cz>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This reverts commit 5da226dbfc ("mm: skip CMA pages when they are not
available") and b7108d6631 ("Multi-gen LRU: skip CMA pages when they are
not eligible").
lruvec->lru_lock is highly contended and is held when calling
isolate_lru_folios. If the lru has a large number of CMA folios
consecutively, while the allocation type requested is not MIGRATE_MOVABLE,
isolate_lru_folios can hold the lock for a very long time while it skips
those. For FIO workload, ~150million order=0 folios were skipped to
isolate a few ZONE_DMA folios [1]. This can cause lockups [1] and high
memory pressure for extended periods of time [2].
Remove skipping CMA for MGLRU as well, as it was introduced in sort_folio
for the same resaon as 5da226dbfc.
[1] https://lore.kernel.org/all/CAOUHufbkhMZYz20aM_3rHZ3OcK4m2puji2FGpUpn_-DevGk3Kg@mail.gmail.com/
[2] https://lore.kernel.org/all/ZrssOrcJIDy8hacI@gmail.com/
[usamaarif642@gmail.com: also revert b7108d6631, per Johannes]
Link: https://lkml.kernel.org/r/9060a32d-b2d7-48c0-8626-1db535653c54@gmail.com
Link: https://lkml.kernel.org/r/357ac325-4c61-497a-92a3-bdbd230d5ec9@gmail.com
Link: https://lkml.kernel.org/r/9060a32d-b2d7-48c0-8626-1db535653c54@gmail.com
Fixes: 5da226dbfc ("mm: skip CMA pages when they are not available")
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zhaoyang Huang <huangzhaoyang@gmail.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fix the condition to exclude the elfcorehdr segment from the SHA digest
calculation.
The j iterator is an index into the output sha_regions[] array, not into
the input image->segment[] array. Once it reaches
image->elfcorehdr_index, all subsequent segments are excluded. Besides,
if the purgatory segment precedes the elfcorehdr segment, the elfcorehdr
may be wrongly included in the calculation.
Link: https://lkml.kernel.org/r/20240805150750.170739-1-petr.tesarik@suse.com
Fixes: f7cc804a9f ("kexec: exclude elfcorehdr from the segment digest")
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After commit a694291a62 ("nilfs2: separate wait function from
nilfs_segctor_write") was applied, the log writing function
nilfs_segctor_do_construct() was able to issue I/O requests continuously
even if user data blocks were split into multiple logs across segments,
but two potential flaws were introduced in its error handling.
First, if nilfs_segctor_begin_construction() fails while creating the
second or subsequent logs, the log writing function returns without
calling nilfs_segctor_abort_construction(), so the writeback flag set on
pages/folios will remain uncleared. This causes page cache operations to
hang waiting for the writeback flag. For example,
truncate_inode_pages_final(), which is called via nilfs_evict_inode() when
an inode is evicted from memory, will hang.
Second, the NILFS_I_COLLECTED flag set on normal inodes remain uncleared.
As a result, if the next log write involves checkpoint creation, that's
fine, but if a partial log write is performed that does not, inodes with
NILFS_I_COLLECTED set are erroneously removed from the "sc_dirty_files"
list, and their data and b-tree blocks may not be written to the device,
corrupting the block mapping.
Fix these issues by uniformly calling nilfs_segctor_abort_construction()
on failure of each step in the loop in nilfs_segctor_do_construct(),
having it clean up logs and segment usages according to progress, and
correcting the conditions for calling nilfs_redirty_inodes() to ensure
that the NILFS_I_COLLECTED flag is cleared.
Link: https://lkml.kernel.org/r/20240814101119.4070-1-konishi.ryusuke@gmail.com
Fixes: a694291a62 ("nilfs2: separate wait function from nilfs_segctor_write")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In an error injection test of a routine for mount-time recovery, KASAN
found a use-after-free bug.
It turned out that if data recovery was performed using partial logs
created by dsync writes, but an error occurred before starting the log
writer to create a recovered checkpoint, the inodes whose data had been
recovered were left in the ns_dirty_files list of the nilfs object and
were not freed.
Fix this issue by cleaning up inodes that have read the recovery data if
the recovery routine fails midway before the log writer starts.
Link: https://lkml.kernel.org/r/20240810065242.3701-1-konishi.ryusuke@gmail.com
Fixes: 0f3e1c7f23 ("nilfs2: recovery functions")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The superblock buffers of nilfs2 can not only be overwritten at runtime
for modifications/repairs, but they are also regularly swapped, replaced
during resizing, and even abandoned when degrading to one side due to
backing device issues. So, accessing them requires mutual exclusion using
the reader/writer semaphore "nilfs->ns_sem".
Some sysfs attribute show methods read this superblock buffer without the
necessary mutual exclusion, which can cause problems with pointer
dereferencing and memory access, so fix it.
Link: https://lkml.kernel.org/r/20240811100320.9913-1-konishi.ryusuke@gmail.com
Fixes: da7141fb78 ("nilfs2: add /sys/fs/nilfs2/<device> group")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since khugepaged was changed to allow retracting page tables in file
mappings without holding the mmap lock, these BUG_ON()s are wrong - get
rid of them.
We could also remove the preceding "if (unlikely(...))" block, but then we
could reach pte_offset_map_lock() with transhuge pages not just for file
mappings but also for anonymous mappings - which would probably be fine
but I think is not necessarily expected.
Link: https://lkml.kernel.org/r/20240813-uffd-thp-flip-fix-v2-2-5efa61078a41@google.com
Fixes: 1d65b771bc ("mm/khugepaged: retract_page_tables() without mmap or vma lock")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "userfaultfd: fix races around pmd_trans_huge() check", v2.
The pmd_trans_huge() code in mfill_atomic() is wrong in three different
ways depending on kernel version:
1. The pmd_trans_huge() check is racy and can lead to a BUG_ON() (if you hit
the right two race windows) - I've tested this in a kernel build with
some extra mdelay() calls. See the commit message for a description
of the race scenario.
On older kernels (before 6.5), I think the same bug can even
theoretically lead to accessing transhuge page contents as a page table
if you hit the right 5 narrow race windows (I haven't tested this case).
2. As pointed out by Qi Zheng, pmd_trans_huge() is not sufficient for
detecting PMDs that don't point to page tables.
On older kernels (before 6.5), you'd just have to win a single fairly
wide race to hit this.
I've tested this on 6.1 stable by racing migration (with a mdelay()
patched into try_to_migrate()) against UFFDIO_ZEROPAGE - on my x86
VM, that causes a kernel oops in ptlock_ptr().
3. On newer kernels (>=6.5), for shmem mappings, khugepaged is allowed
to yank page tables out from under us (though I haven't tested that),
so I think the BUG_ON() checks in mfill_atomic() are just wrong.
I decided to write two separate fixes for these (one fix for bugs 1+2, one
fix for bug 3), so that the first fix can be backported to kernels
affected by bugs 1+2.
This patch (of 2):
This fixes two issues.
I discovered that the following race can occur:
mfill_atomic other thread
============ ============
<zap PMD>
pmdp_get_lockless() [reads none pmd]
<bail if trans_huge>
<if none:>
<pagefault creates transhuge zeropage>
__pte_alloc [no-op]
<zap PMD>
<bail if pmd_trans_huge(*dst_pmd)>
BUG_ON(pmd_none(*dst_pmd))
I have experimentally verified this in a kernel with extra mdelay() calls;
the BUG_ON(pmd_none(*dst_pmd)) triggers.
On kernels newer than commit 0d940a9b27 ("mm/pgtable: allow
pte_offset_map[_lock]() to fail"), this can't lead to anything worse than
a BUG_ON(), since the page table access helpers are actually designed to
deal with page tables concurrently disappearing; but on older kernels
(<=6.4), I think we could probably theoretically race past the two
BUG_ON() checks and end up treating a hugepage as a page table.
The second issue is that, as Qi Zheng pointed out, there are other types
of huge PMDs that pmd_trans_huge() can't catch: devmap PMDs and swap PMDs
(in particular, migration PMDs).
On <=6.4, this is worse than the first issue: If mfill_atomic() runs on a
PMD that contains a migration entry (which just requires winning a single,
fairly wide race), it will pass the PMD to pte_offset_map_lock(), which
assumes that the PMD points to a page table.
Breakage follows: First, the kernel tries to take the PTE lock (which will
crash or maybe worse if there is no "struct page" for the address bits in
the migration entry PMD - I think at least on X86 there usually is no
corresponding "struct page" thanks to the PTE inversion mitigation, amd64
looks different).
If that didn't crash, the kernel would next try to write a PTE into what
it wrongly thinks is a page table.
As part of fixing these issues, get rid of the check for pmd_trans_huge()
before __pte_alloc() - that's redundant, we're going to have to check for
that after the __pte_alloc() anyway.
Backport note: pmdp_get_lockless() is pmd_read_atomic() in older kernels.
Link: https://lkml.kernel.org/r/20240813-uffd-thp-flip-fix-v2-0-5efa61078a41@google.com
Link: https://lkml.kernel.org/r/20240813-uffd-thp-flip-fix-v2-1-5efa61078a41@google.com
Fixes: c1a4de99fa ("userfaultfd: mcopy_atomic|mfill_zeropage: UFFDIO_COPY|UFFDIO_ZEROPAGE preparation")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 8c61291fd8 ("mm: fix incorrect vbq reference in
purge_fragmented_block") extended the 'vmap_block' structure to contain a
'cpu' field which is set at allocation time to the id of the initialising
CPU.
When a new 'vmap_block' is being instantiated by new_vmap_block(), the
partially initialised structure is added to the local 'vmap_block_queue'
xarray before the 'cpu' field has been initialised. If another CPU is
concurrently walking the xarray (e.g. via vm_unmap_aliases()), then it
may perform an out-of-bounds access to the remote queue thanks to an
uninitialised index.
This has been observed as UBSAN errors in Android:
| Internal error: UBSAN: array index out of bounds: 00000000f2005512 [#1] PREEMPT SMP
|
| Call trace:
| purge_fragmented_block+0x204/0x21c
| _vm_unmap_aliases+0x170/0x378
| vm_unmap_aliases+0x1c/0x28
| change_memory_common+0x1dc/0x26c
| set_memory_ro+0x18/0x24
| module_enable_ro+0x98/0x238
| do_init_module+0x1b0/0x310
Move the initialisation of 'vb->cpu' in new_vmap_block() ahead of the
addition to the xarray.
Link: https://lkml.kernel.org/r/20240812171606.17486-1-will@kernel.org
Fixes: 8c61291fd8 ("mm: fix incorrect vbq reference in purge_fragmented_block")
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Cc: Hailong.Liu <hailong.liu@oppo.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The __NR_mmap isn't found on armhf. The mmap() is commonly available
system call and its wrapper is present on all architectures. So it should
be used directly. It solves problem for armhf and doesn't create problem
for other architectures.
Remove sys_mmap() functions as they aren't doing anything else other than
calling mmap(). There is no need to set errno = 0 manually as glibc
always resets it.
For reference errors are as following:
CC seal_elf
seal_elf.c: In function 'sys_mmap':
seal_elf.c:39:33: error: '__NR_mmap' undeclared (first use in this function)
39 | sret = (void *) syscall(__NR_mmap, addr, len, prot,
| ^~~~~~~~~
mseal_test.c: In function 'sys_mmap':
mseal_test.c:90:33: error: '__NR_mmap' undeclared (first use in this function)
90 | sret = (void *) syscall(__NR_mmap, addr, len, prot,
| ^~~~~~~~~
Link: https://lkml.kernel.org/r/20240809082511.497266-1-usama.anjum@collabora.com
Fixes: 4926c7a52d ("selftest mm/mseal memory sealing")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Document the compatible strings for the Sipeed LicheeRV Nano B board which
uses the SOPHGO SG2002 SoC.
Signed-off-by: Thomas Bonnefille <thomas.bonnefille@bootlin.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Inochi Amaoto <inochiama@outlook.com>
Link: https://lore.kernel.org/r/20240711-sg2002-v4-2-d97ec2367095@bootlin.com
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Signed-off-by: Chen Wang <unicorn_wang@outlook.com>
A mac_id as an instance in firmware has to be assigned for each station
including AP and connected stations. Firmware will use the mac_id to
control TX rate and do statistics.
Assignment rule is to assign mac_id to each vif when adding vif.
For station mode, sta->mac_id will reuse vif->mac_id. For AP mode,
dynamically allocate an sta->mac_id to a station, and vif->mac_id is
used to send broadcast/multicast packets which are not belong to
a station. For example,
vif->mac_id sta->mac_id
vif0 (STA mode) 0 0
vif1 (AP mode) 1 2...
By the way, remove unused RTW_BC_MC_MACID, which was planed to send
broadcast/multicast packets on fixed mac_id.
Tested-on RTL8822CE with STA + AP SCC mode.
Link: https://lore.kernel.org/linux-wireless/e4be0a75-43b2-4ae5-9aab-5c4a88e78097@gmail.com/
Cc: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240819025248.17939-1-pkshih@realtek.com
