6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Suren Baghdasaryan <surenb@xxxxxxxxxx> [ Upstream commit 6ab42fe21c84d72da752923b4bd7075344f4a362 ] pgalloc_tag_sub() might call page_ext_put() using a page different from the one used in page_ext_get() call. This does not pose an issue since page_ext_put() ignores this parameter as long as it's non-NULL but technically this is wrong. Fix it by storing the original page used in page_ext_get() and passing it to page_ext_put(). Link: https://lkml.kernel.org/r/20240711220457.1751071-3-surenb@xxxxxxxxxx Fixes: be25d1d4e822 ("mm: create new codetag references during page splitting") Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx> Cc: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx> Cc: Sourav Panda <souravpanda@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/linux/pgalloc_tag.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/pgalloc_tag.h b/include/linux/pgalloc_tag.h index acb1e9ce79815..18cd0c0c73d93 100644 --- a/include/linux/pgalloc_tag.h +++ b/include/linux/pgalloc_tag.h @@ -71,6 +71,7 @@ static inline void pgalloc_tag_sub(struct page *page, unsigned int nr) static inline void pgalloc_tag_split(struct page *page, unsigned int nr) { int i; + struct page_ext *first_page_ext; struct page_ext *page_ext; union codetag_ref *ref; struct alloc_tag *tag; @@ -78,7 +79,7 @@ static inline void pgalloc_tag_split(struct page *page, unsigned int nr) if (!mem_alloc_profiling_enabled()) return; - page_ext = page_ext_get(page); + first_page_ext = page_ext = page_ext_get(page); if (unlikely(!page_ext)) return; @@ -94,7 +95,7 @@ static inline void pgalloc_tag_split(struct page *page, unsigned int nr) page_ext = page_ext_next(page_ext); } out: - page_ext_put(page_ext); + page_ext_put(first_page_ext); } static inline struct alloc_tag *pgalloc_tag_get(struct page *page) -- 2.43.0
