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| author | David Wang <00107082@163.com> | 2024-12-13 09:33:32 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-12-18 19:04:46 -0800 |
| commit | 640a603943a7659340c10044c0a1c98ae4e13189 (patch) | |
| tree | fbe3be6535a01d7f7dd285216a8ccef7db88d521 | |
| parent | 30c2de0a267c04046d89e678cc0067a9cfb455df (diff) | |
| download | linux-640a603943a7659340c10044c0a1c98ae4e13189.tar.gz linux-640a603943a7659340c10044c0a1c98ae4e13189.tar.bz2 linux-640a603943a7659340c10044c0a1c98ae4e13189.zip | |
mm/codetag: clear tags before swap
When CONFIG_MEM_ALLOC_PROFILING_DEBUG is set, kernel WARN would be
triggered when calling __alloc_tag_ref_set() during swap:
alloc_tag was not cleared (got tag for mm/filemap.c:1951)
WARNING: CPU: 0 PID: 816 at ./include/linux/alloc_tag.h...
Clear code tags before swap can fix the warning. And this patch also fix
a potential invalid address dereference in alloc_tag_add_check() when
CONFIG_MEM_ALLOC_PROFILING_DEBUG is set and ref->ct is CODETAG_EMPTY,
which is defined as ((void *)1).
Link: https://lkml.kernel.org/r/20241213013332.89910-1-00107082@163.com
Fixes: 51f43d5d82ed ("mm/codetag: swap tags when migrate pages")
Signed-off-by: David Wang <00107082@163.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202412112227.df61ebb-lkp@intel.com
Acked-by: Suren Baghdasaryan <surenb@google.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/alloc_tag.h | 2 | ||||
| -rw-r--r-- | lib/alloc_tag.c | 7 |
2 files changed, 8 insertions, 1 deletions
diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index 7c0786bdf9af..cba024bf2db3 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -135,7 +135,7 @@ static inline struct alloc_tag_counters alloc_tag_read(struct alloc_tag *tag) #ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag) { - WARN_ONCE(ref && ref->ct, + WARN_ONCE(ref && ref->ct && !is_codetag_empty(ref), "alloc_tag was not cleared (got tag for %s:%u)\n", ref->ct->filename, ref->ct->lineno); diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c index 35f7560a309a..3a0413462e9f 100644 --- a/lib/alloc_tag.c +++ b/lib/alloc_tag.c @@ -209,6 +209,13 @@ void pgalloc_tag_swap(struct folio *new, struct folio *old) return; } + /* + * Clear tag references to avoid debug warning when using + * __alloc_tag_ref_set() with non-empty reference. + */ + set_codetag_empty(&ref_old); + set_codetag_empty(&ref_new); + /* swap tags */ __alloc_tag_ref_set(&ref_old, tag_new); update_page_tag_ref(handle_old, &ref_old); |