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alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting

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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@google.com
Fixes: be25d1d4e8 ("mm: create new codetag references during page splitting")
Signed-off-by: Suren Baghdasaryan <surenb@google.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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Suren Baghdasaryan 2024-07-11 15:04:57 -07:00 committed by Andrew Morton
parent fd8acc0097
commit 6ab42fe21c
1 changed files with 3 additions and 2 deletions
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5
include/linux/pgalloc_tag.h
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@ -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)