The quilt patch titled
Subject: mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list
has been removed from the -mm tree. Its filename was
mm-vmscan-fix-hwpoisoned-large-folio-handling-in-shrink_folio_list.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Jinjiang Tu <tujinjiang(a)huawei.com>
Subject: mm/vmscan: fix hwpoisoned large folio handling in shrink_folio_list
Date: Fri, 27 Jun 2025 20:57:46 +0800
In shrink_folio_list(), the hwpoisoned folio may be large folio, which
can't be handled by unmap_poisoned_folio(). For THP, try_to_unmap_one()
must be passed with TTU_SPLIT_HUGE_PMD to split huge PMD first and then
retry. Without TTU_SPLIT_HUGE_PMD, we will trigger null-ptr deref of
pvmw.pte. Even we passed TTU_SPLIT_HUGE_PMD, we will trigger a
WARN_ON_ONCE due to the page isn't in swapcache.
Since UCE is rare in real world, and race with reclaimation is more rare,
just skipping the hwpoisoned large folio is enough. memory_failure() will
handle it if the UCE is triggered again.
This happens when memory reclaim for large folio races with
memory_failure(), and will lead to kernel panic. The race is as
follows:
cpu0 cpu1
shrink_folio_list memory_failure
TestSetPageHWPoison
unmap_poisoned_folio
--> trigger BUG_ON due to
unmap_poisoned_folio couldn't
handle large folio
[tujinjiang(a)huawei.com: add comment to unmap_poisoned_folio()]
Link: https://lkml.kernel.org/r/69fd4e00-1b13-d5f7-1c82-705c7d977ea4@huawei.com
Link: https://lkml.kernel.org/r/20250627125747.3094074-2-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang(a)huawei.com>
Fixes: 1b0449544c64 ("mm/vmscan: don't try to reclaim hwpoison folio")
Reported-by: syzbot+3b220254df55d8ca8a61(a)syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68412d57.050a0220.2461cf.000e.GAE@google.com/
Acked-by: David Hildenbrand <david(a)redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe(a)huawei.com>
Acked-by: Zi Yan <ziy(a)nvidia.com>
Reviewed-by: Oscar Salvador <osalvador(a)suse.de>
Cc: Kefeng Wang <wangkefeng.wang(a)huawei.com>
Cc: Michal Hocko <mhocko(a)kernel.org>
Cc: Oscar Salvador <osalvador(a)suse.de>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/memory-failure.c | 4 ++++
mm/vmscan.c | 8 ++++++++
2 files changed, 12 insertions(+)
--- a/mm/memory-failure.c~mm-vmscan-fix-hwpoisoned-large-folio-handling-in-shrink_folio_list
+++ a/mm/memory-failure.c
@@ -1561,6 +1561,10 @@ static int get_hwpoison_page(struct page
return ret;
}
+/*
+ * The caller must guarantee the folio isn't large folio, except hugetlb.
+ * try_to_unmap() can't handle it.
+ */
int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill)
{
enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_SYNC | TTU_HWPOISON;
--- a/mm/vmscan.c~mm-vmscan-fix-hwpoisoned-large-folio-handling-in-shrink_folio_list
+++ a/mm/vmscan.c
@@ -1138,6 +1138,14 @@ retry:
goto keep;
if (folio_contain_hwpoisoned_page(folio)) {
+ /*
+ * unmap_poisoned_folio() can't handle large
+ * folio, just skip it. memory_failure() will
+ * handle it if the UCE is triggered again.
+ */
+ if (folio_test_large(folio))
+ goto keep_locked;
+
unmap_poisoned_folio(folio, folio_pfn(folio), false);
folio_unlock(folio);
folio_put(folio);
_
Patches currently in -mm which might be from tujinjiang(a)huawei.com are
mm-memory_hotplug-fix-hwpoisoned-large-folio-handling-in-do_migrate_range.patch
From: Steve French <stfrench(a)microsoft.com>
Some servers (including Samba), support the SMB3.1.1 POSIX Extensions (which use reparse
points for handling special files) but do not properly advertise file system attribute
FILE_SUPPORTS_REPARSE_POINTS. Although we don't check for this attribute flag when
querying special file information, we do check it when creating special files which
causes them to fail unnecessarily. If we have negotiated SMB3.1.1 POSIX Extensions
with the server we can expect the server to support creating special files via
reparse points, and even if the server fails the operation due to really forbidding
creating special files, then it should be no problem and is more likely to return a
more accurate rc in any case (e.g. EACCES instead of EOPNOTSUPP).
Allow creating special files as long as the server supports either reparse points
or the SMB3.1.1 POSIX Extensions (note that if the "sfu" mount option is specified
it uses a different way of storing special files that does not rely on reparse points).
Cc: <stable(a)vger.kernel.org>
Fixes: 6c06be908ca19 ("cifs: Check if server supports reparse points before using them")
Acked-by: Ralph Boehme <slow(a)samba.org>
Acked-by: Paulo Alcantara (Red Hat) <pc(a)manguebit.org>
Signed-off-by: Steve French <stfrench(a)microsoft.com>
---
fs/smb/client/smb2inode.c | 3 ++-
fs/smb/client/smb2ops.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 2a3e46b8e15a..a11a2a693c51 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -1346,7 +1346,8 @@ struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
* empty object on the server.
*/
if (!(le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS))
- return ERR_PTR(-EOPNOTSUPP);
+ if (!tcon->posix_extensions)
+ return ERR_PTR(-EOPNOTSUPP);
oparms = CIFS_OPARMS(cifs_sb, tcon, full_path,
SYNCHRONIZE | DELETE |
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index cb659256d219..938a8a7c5d21 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -5260,7 +5260,8 @@ static int smb2_make_node(unsigned int xid, struct inode *inode,
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
rc = cifs_sfu_make_node(xid, inode, dentry, tcon,
full_path, mode, dev);
- } else if (le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS) {
+ } else if ((le32_to_cpu(tcon->fsAttrInfo.Attributes) & FILE_SUPPORTS_REPARSE_POINTS)
+ || (tcon->posix_extensions)) {
rc = smb2_mknod_reparse(xid, inode, dentry, tcon,
full_path, mode, dev);
}
--
2.34.1
The quilt patch titled
Subject: mm/hmm: move pmd_to_hmm_pfn_flags() to the respective #ifdeffery
has been removed from the -mm tree. Its filename was
mm-hmm-move-pmd_to_hmm_pfn_flags-to-the-respective-ifdeffery.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com>
Subject: mm/hmm: move pmd_to_hmm_pfn_flags() to the respective #ifdeffery
Date: Thu, 10 Jul 2025 11:23:53 +0300
When pmd_to_hmm_pfn_flags() is unused, it prevents kernel builds with
clang, `make W=1` and CONFIG_TRANSPARENT_HUGEPAGE=n:
mm/hmm.c:186:29: warning: unused function 'pmd_to_hmm_pfn_flags' [-Wunused-function]
Fix this by moving the function to the respective existing ifdeffery
for its the only user.
See also:
6863f5643dd7 ("kbuild: allow Clang to find unused static inline functions for W=1 build")
Link: https://lkml.kernel.org/r/20250710082403.664093-1-andriy.shevchenko@linux.i…
Fixes: 992de9a8b751 ("mm/hmm: allow to mirror vma of a file on a DAX backed filesystem")
Signed-off-by: Andy Shevchenko <andriy.shevchenko(a)linux.intel.com>
Reviewed-by: Leon Romanovsky <leonro(a)nvidia.com>
Reviewed-by: Alistair Popple <apopple(a)nvidia.com>
Cc: Andriy Shevchenko <andriy.shevchenko(a)linux.intel.com>
Cc: Bill Wendling <morbo(a)google.com>
Cc: Jerome Glisse <jglisse(a)redhat.com>
Cc: Justin Stitt <justinstitt(a)google.com>
Cc: Nathan Chancellor <nathan(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/hmm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/hmm.c~mm-hmm-move-pmd_to_hmm_pfn_flags-to-the-respective-ifdeffery
+++ a/mm/hmm.c
@@ -183,6 +183,7 @@ static inline unsigned long hmm_pfn_flag
return order << HMM_PFN_ORDER_SHIFT;
}
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline unsigned long pmd_to_hmm_pfn_flags(struct hmm_range *range,
pmd_t pmd)
{
@@ -193,7 +194,6 @@ static inline unsigned long pmd_to_hmm_p
hmm_pfn_flags_order(PMD_SHIFT - PAGE_SHIFT);
}
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static int hmm_vma_handle_pmd(struct mm_walk *walk, unsigned long addr,
unsigned long end, unsigned long hmm_pfns[],
pmd_t pmd)
_
Patches currently in -mm which might be from andriy.shevchenko(a)linux.intel.com are
The quilt patch titled
Subject: mm/damon/core: commit damos->target_nid
has been removed from the -mm tree. Its filename was
mm-damon-core-commit-damos-target_nid.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Bijan Tabatabai <bijantabatab(a)micron.com>
Subject: mm/damon/core: commit damos->target_nid
Date: Tue, 8 Jul 2025 19:47:29 -0500
When committing new scheme parameters from the sysfs, the target_nid field
of the damos struct would not be copied. This would result in the
target_nid field to retain its original value, despite being updated in
the sysfs interface.
This patch fixes this issue by copying target_nid in damos_commit().
Link: https://lkml.kernel.org/r/20250709004729.17252-1-bijan311@gmail.com
Fixes: 83dc7bbaecae ("mm/damon/sysfs: use damon_commit_ctx()")
Signed-off-by: Bijan Tabatabai <bijantabatab(a)micron.com>
Reviewed-by: SeongJae Park <sj(a)kernel.org>
Cc: Jonathan Corbet <corbet(a)lwn.net>
Cc: Ravi Shankar Jonnalagadda <ravis.opensrc(a)micron.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/damon/core.c | 1 +
1 file changed, 1 insertion(+)
--- a/mm/damon/core.c~mm-damon-core-commit-damos-target_nid
+++ a/mm/damon/core.c
@@ -978,6 +978,7 @@ static int damos_commit(struct damos *ds
return err;
dst->wmarks = src->wmarks;
+ dst->target_nid = src->target_nid;
err = damos_commit_filters(dst, src);
return err;
_
Patches currently in -mm which might be from bijantabatab(a)micron.com are
The patch titled
Subject: mm: swap: correctly use maxpages in swapon syscall to avoid potential deadloop
has been added to the -mm mm-new branch. Its filename is
mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-new branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews. Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kemeng Shi <shikemeng(a)huaweicloud.com>
Subject: mm: swap: correctly use maxpages in swapon syscall to avoid potential deadloop
Date: Fri, 18 Jul 2025 14:51:39 +0800
ensure si->pages == si->max - 1 after setup_swap_extents()
Link: https://lkml.kernel.org/r/20250522122554.12209-3-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20250718065139.61989-1-shikemeng@huaweicloud.com
Fixes: 661383c6111a ("mm: swap: relaim the cached parts that got scanned")
Signed-off-by: Kemeng Shi <shikemeng(a)huaweicloud.com>
Reviewed-by: Baoquan He <bhe(a)redhat.com>
Cc: Johannes Weiner <hannes(a)cmpxchg.org>
Cc: Kairui Song <kasong(a)tencent.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/swapfile.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/mm/swapfile.c~mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop-fix
+++ a/mm/swapfile.c
@@ -3357,6 +3357,12 @@ SYSCALL_DEFINE2(swapon, const char __use
error = nr_extents;
goto bad_swap_unlock_inode;
}
+ if (si->pages != si->max - 1) {
+ pr_err("swap:%u != (max:%u - 1)\n", si->pages, si->max);
+ error = -EINVAL;
+ goto bad_swap_unlock_inode;
+ }
+
maxpages = si->max;
/* OK, set up the swap map and apply the bad block list */
_
Patches currently in -mm which might be from shikemeng(a)huaweicloud.com are
mm-swap-move-nr_swap_pages-counter-decrement-from-folio_alloc_swap-to-swap_range_alloc.patch
mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop.patch
mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop-fix.patch
mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch
mm-swap-remove-stale-comment-stale-comment-in-cluster_alloc_swap_entry.patch
The patch titled
Subject: mm/damon/core: commit damos_quota_goal->nid
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-damon-core-commit-damos_quota_goal-nid.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche…
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: SeongJae Park <sj(a)kernel.org>
Subject: mm/damon/core: commit damos_quota_goal->nid
Date: Sat, 19 Jul 2025 11:19:32 -0700
DAMOS quota goal uses 'nid' field when the metric is
DAMOS_QUOTA_NODE_MEM_{USED,FREE}_BP. But the goal commit function is not
updating the goal's nid field. Fix it.
Link: https://lkml.kernel.org/r/20250719181932.72944-1-sj@kernel.org
Fixes: 0e1c773b501f ("mm/damon/core: introduce damos quota goal metrics for memory node utilization") [6.16.x]
Signed-off-by: SeongJae Park <sj(a)kernel.org>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/damon/core.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
--- a/mm/damon/core.c~mm-damon-core-commit-damos_quota_goal-nid
+++ a/mm/damon/core.c
@@ -754,6 +754,19 @@ static struct damos_quota_goal *damos_nt
return NULL;
}
+static void damos_commit_quota_goal_union(
+ struct damos_quota_goal *dst, struct damos_quota_goal *src)
+{
+ switch (dst->metric) {
+ case DAMOS_QUOTA_NODE_MEM_USED_BP:
+ case DAMOS_QUOTA_NODE_MEM_FREE_BP:
+ dst->nid = src->nid;
+ break;
+ default:
+ break;
+ }
+}
+
static void damos_commit_quota_goal(
struct damos_quota_goal *dst, struct damos_quota_goal *src)
{
@@ -762,6 +775,7 @@ static void damos_commit_quota_goal(
if (dst->metric == DAMOS_QUOTA_USER_INPUT)
dst->current_value = src->current_value;
/* keep last_psi_total as is, since it will be updated in next cycle */
+ damos_commit_quota_goal_union(dst, src);
}
/**
@@ -795,6 +809,7 @@ int damos_commit_quota_goals(struct damo
src_goal->metric, src_goal->target_value);
if (!new_goal)
return -ENOMEM;
+ damos_commit_quota_goal_union(new_goal, src_goal);
damos_add_quota_goal(dst, new_goal);
}
return 0;
_
Patches currently in -mm which might be from sj(a)kernel.org are
mm-damon-core-commit-damos_quota_goal-nid.patch
samples-damon-wsse-rename-to-have-damon_sample_-prefix.patch
samples-damon-prcl-rename-to-have-damon_sample_-prefix.patch
samples-damon-mtier-rename-to-have-damon_sample_-prefix.patch
mm-damon-sysfs-use-damon-core-api-damon_is_running.patch
mm-damon-sysfs-dont-hold-kdamond_lock-in-before_terminate.patch
docs-mm-damon-maintainer-profile-update-for-mm-new-tree.patch
mm-damon-add-struct-damos_migrate_dests.patch
mm-damon-core-add-damos-migrate_dests-field.patch
mm-damon-sysfs-schemes-implement-damos-action-destinations-directory.patch
mm-damon-sysfs-schemes-set-damos-migrate_dests.patch
docs-abi-damon-document-schemes-dests-directory.patch
docs-admin-guide-mm-damon-usage-document-dests-directory.patch
mm-damon-accept-parallel-damon_call-requests.patch
mm-damon-core-introduce-repeat-mode-damon_call.patch
mm-damon-stat-use-damon_call-repeat-mode-instead-of-damon_callback.patch
mm-damon-reclaim-use-damon_call-repeat-mode-instead-of-damon_callback.patch
mm-damon-lru_sort-use-damon_call-repeat-mode-instead-of-damon_callback.patch
samples-damon-prcl-use-damon_call-repeat-mode-instead-of-damon_callback.patch
samples-damon-wsse-use-damon_call-repeat-mode-instead-of-damon_callback.patch
mm-damon-core-do-not-call-opscleanup-when-destroying-targets.patch
mm-damon-core-add-cleanup_target-ops-callback.patch
mm-damon-core-add-cleanup_target-ops-callback-fix.patch
mm-damon-core-add-cleanup_target-ops-callback-fix-2.patch
mm-damon-vaddr-put-pid-in-cleanup_target.patch
mm-damon-sysfs-remove-damon_sysfs_destroy_targets.patch
mm-damon-core-destroy-targets-when-kdamond_fn-finish.patch
mm-damon-sysfs-remove-damon_sysfs_before_terminate.patch
mm-damon-core-remove-damon_callback.patch
mm-damon-sysfs-implement-refresh_ms-file-under-kdamond-directory.patch
mm-damon-sysfs-implement-refresh_ms-file-internal-work.patch
docs-admin-guide-mm-damon-usage-document-refresh_ms-file.patch
docs-abi-damon-update-for-refresh_ms.patch
From: Steven Rostedt <rostedt(a)goodmis.org>
When a module is loaded, it adds trace events defined by the module. It
may also need to modify the modules trace printk formats to replace enum
names with their values.
If two modules are loaded at the same time, the adding of the event to the
ftrace_events list can corrupt the walking of the list in the code that is
modifying the printk format strings and crash the kernel.
The addition of the event should take the trace_event_sem for write while
it adds the new event.
Also add a lockdep_assert_held() on that semaphore in
__trace_add_event_dirs() as it iterates the list.
Cc: stable(a)vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org>
Link: https://lore.kernel.org/20250718223158.799bfc0c@batman.local.home
Reported-by: Fusheng Huang(黄富生) <Fusheng.Huang(a)luxshare-ict.com>
Closes: https://lore.kernel.org/all/20250717105007.46ccd18f@batman.local.home/
Fixes: 110bf2b764eb6 ("tracing: add protection around module events unload")
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
kernel/trace/trace_events.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 120531268abf..d01e5c910ce1 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -3136,7 +3136,10 @@ __register_event(struct trace_event_call *call, struct module *mod)
if (ret < 0)
return ret;
+ down_write(&trace_event_sem);
list_add(&call->list, &ftrace_events);
+ up_write(&trace_event_sem);
+
if (call->flags & TRACE_EVENT_FL_DYNAMIC)
atomic_set(&call->refcnt, 0);
else
@@ -3750,6 +3753,8 @@ __trace_add_event_dirs(struct trace_array *tr)
struct trace_event_call *call;
int ret;
+ lockdep_assert_held(&trace_event_sem);
+
list_for_each_entry(call, &ftrace_events, list) {
ret = __trace_add_new_event(call, tr);
if (ret < 0)
--
2.47.2
From: Tomas Glozar <tglozar(a)redhat.com>
We have observed kernel panics when using timerlat with stack saving,
with the following dmesg output:
memcpy: detected buffer overflow: 88 byte write of buffer size 0
WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0
CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy)
Call Trace:
<TASK>
? trace_buffer_lock_reserve+0x2a/0x60
__fortify_panic+0xd/0xf
__timerlat_dump_stack.cold+0xd/0xd
timerlat_dump_stack.part.0+0x47/0x80
timerlat_fd_read+0x36d/0x390
vfs_read+0xe2/0x390
? syscall_exit_to_user_mode+0x1d5/0x210
ksys_read+0x73/0xe0
do_syscall_64+0x7b/0x160
? exc_page_fault+0x7e/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
__timerlat_dump_stack() constructs the ftrace stack entry like this:
struct stack_entry *entry;
...
memcpy(&entry->caller, fstack->calls, size);
entry->size = fstack->nr_entries;
Since commit e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to
kernel_stack event structure"), struct stack_entry marks its caller
field with __counted_by(size). At the time of the memcpy, entry->size
contains garbage from the ringbuffer, which under some circumstances is
zero, triggering a kernel panic by buffer overflow.
Populate the size field before the memcpy so that the out-of-bounds
check knows the correct size. This is analogous to
__ftrace_trace_stack().
Cc: stable(a)vger.kernel.org
Cc: John Kacur <jkacur(a)redhat.com>
Cc: Luis Goncalves <lgoncalv(a)redhat.com>
Cc: Attila Fazekas <afazekas(a)redhat.com>
Link: https://lore.kernel.org/20250716143601.7313-1-tglozar@redhat.com
Fixes: e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure")
Signed-off-by: Tomas Glozar <tglozar(a)redhat.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org>
---
kernel/trace/trace_osnoise.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index 6819b93309ce..fd259da0aa64 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -637,8 +637,8 @@ __timerlat_dump_stack(struct trace_buffer *buffer, struct trace_stack *fstack, u
entry = ring_buffer_event_data(event);
- memcpy(&entry->caller, fstack->calls, size);
entry->size = fstack->nr_entries;
+ memcpy(&entry->caller, fstack->calls, size);
trace_buffer_unlock_commit_nostack(buffer, event);
}
--
2.47.2