From 640a603943a7659340c10044c0a1c98ae4e13189 Mon Sep 17 00:00:00 2001 From: David Wang <00107082@163.com> Date: Fri, 13 Dec 2024 09:33:32 +0800 Subject: 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 Closes: https://lore.kernel.org/oe-lkp/202412112227.df61ebb-lkp@intel.com Acked-by: Suren Baghdasaryan Cc: Kent Overstreet Cc: Yu Zhao Cc: Signed-off-by: Andrew Morton --- include/linux/alloc_tag.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/alloc_tag.h') 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); -- cgit v1.3 From 60da7445a142bd15e67f3cda915497781c3f781f Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan Date: Fri, 29 Nov 2024 16:14:23 -0800 Subject: alloc_tag: fix set_codetag_empty() when !CONFIG_MEM_ALLOC_PROFILING_DEBUG It was recently noticed that set_codetag_empty() might be used not only to mark NULL alloctag references as empty to avoid warnings but also to reset valid tags (in clear_page_tag_ref()). Since set_codetag_empty() is defined as NOOP for CONFIG_MEM_ALLOC_PROFILING_DEBUG=n, such use of set_codetag_empty() leads to subtle bugs. Fix set_codetag_empty() for CONFIG_MEM_ALLOC_PROFILING_DEBUG=n to reset the tag reference. Link: https://lkml.kernel.org/r/20241130001423.1114965-2-surenb@google.com Fixes: a8fc28dad6d5 ("alloc_tag: introduce clear_page_tag_ref() helper function") Signed-off-by: Suren Baghdasaryan Reported-by: David Wang <00107082@163.com> Closes: https://lore.kernel.org/lkml/20241124074318.399027-1-00107082@163.com/ Cc: David Wang <00107082@163.com> Cc: Kent Overstreet Cc: Mike Rapoport (Microsoft) Cc: Pasha Tatashin Cc: Sourav Panda Cc: Yu Zhao Cc: Signed-off-by: Andrew Morton --- include/linux/alloc_tag.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux/alloc_tag.h') diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h index cba024bf2db3..0bbbe537c5f9 100644 --- a/include/linux/alloc_tag.h +++ b/include/linux/alloc_tag.h @@ -63,7 +63,12 @@ static inline void set_codetag_empty(union codetag_ref *ref) #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ static inline bool is_codetag_empty(union codetag_ref *ref) { return false; } -static inline void set_codetag_empty(union codetag_ref *ref) {} + +static inline void set_codetag_empty(union codetag_ref *ref) +{ + if (ref) + ref->ct = NULL; +} #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */ -- cgit v1.3