The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x be8250786ca94952a19ce87f98ad9906448bc9ef # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025050521-crispy-study-e836@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From be8250786ca94952a19ce87f98ad9906448bc9ef Mon Sep 17 00:00:00 2001 From: Zhenhua Huang quic_zhenhuah@quicinc.com Date: Mon, 21 Apr 2025 15:52:32 +0800 Subject: [PATCH] mm, slab: clean up slab->obj_exts always
When memory allocation profiling is disabled at runtime or due to an error, shutdown_mem_profiling() is called: slab->obj_exts which previously allocated remains. It won't be cleared by unaccount_slab() because of mem_alloc_profiling_enabled() not true. It's incorrect, slab->obj_exts should always be cleaned up in unaccount_slab() to avoid following error:
[...]BUG: Bad page state in process... .. [...]page dumped because: page still charged to cgroup
[andriy.shevchenko@linux.intel.com: fold need_slab_obj_ext() into its only user] Fixes: 21c690a349ba ("mm: introduce slabobj_ext to support slab object extensions") Cc: stable@vger.kernel.org Signed-off-by: Zhenhua Huang quic_zhenhuah@quicinc.com Acked-by: David Rientjes rientjes@google.com Acked-by: Harry Yoo harry.yoo@oracle.com Tested-by: Harry Yoo harry.yoo@oracle.com Acked-by: Suren Baghdasaryan surenb@google.com Link: https://patch.msgid.link/20250421075232.2165527-1-quic_zhenhuah@quicinc.com Signed-off-by: Vlastimil Babka vbabka@suse.cz
diff --git a/mm/slub.c b/mm/slub.c index dc9e729e1d26..be8b09e09d30 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2028,8 +2028,7 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, return 0; }
-/* Should be called only if mem_alloc_profiling_enabled() */ -static noinline void free_slab_obj_exts(struct slab *slab) +static inline void free_slab_obj_exts(struct slab *slab) { struct slabobj_ext *obj_exts;
@@ -2049,18 +2048,6 @@ static noinline void free_slab_obj_exts(struct slab *slab) slab->obj_exts = 0; }
-static inline bool need_slab_obj_ext(void) -{ - if (mem_alloc_profiling_enabled()) - return true; - - /* - * CONFIG_MEMCG creates vector of obj_cgroup objects conditionally - * inside memcg_slab_post_alloc_hook. No other users for now. - */ - return false; -} - #else /* CONFIG_SLAB_OBJ_EXT */
static inline void init_slab_obj_exts(struct slab *slab) @@ -2077,11 +2064,6 @@ static inline void free_slab_obj_exts(struct slab *slab) { }
-static inline bool need_slab_obj_ext(void) -{ - return false; -} - #endif /* CONFIG_SLAB_OBJ_EXT */
#ifdef CONFIG_MEM_ALLOC_PROFILING @@ -2129,7 +2111,7 @@ __alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) static inline void alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) { - if (need_slab_obj_ext()) + if (mem_alloc_profiling_enabled()) __alloc_tagging_slab_alloc_hook(s, object, flags); }
@@ -2601,8 +2583,12 @@ static __always_inline void account_slab(struct slab *slab, int order, static __always_inline void unaccount_slab(struct slab *slab, int order, struct kmem_cache *s) { - if (memcg_kmem_online() || need_slab_obj_ext()) - free_slab_obj_exts(slab); + /* + * The slab object extensions should now be freed regardless of + * whether mem_alloc_profiling_enabled() or not because profiling + * might have been disabled after slab->obj_exts got allocated. + */ + free_slab_obj_exts(slab);
mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), -(PAGE_SIZE << order));
From: Zhenhua Huang quic_zhenhuah@quicinc.com
When memory allocation profiling is disabled at runtime or due to an error, shutdown_mem_profiling() is called: slab->obj_exts which previously allocated remains. It won't be cleared by unaccount_slab() because of mem_alloc_profiling_enabled() not true. It's incorrect, slab->obj_exts should always be cleaned up in unaccount_slab() to avoid following error:
[...]BUG: Bad page state in process... .. [...]page dumped because: page still charged to cgroup
[andriy.shevchenko@linux.intel.com: fold need_slab_obj_ext() into its only user] Fixes: 21c690a349ba ("mm: introduce slabobj_ext to support slab object extensions") Cc: stable@vger.kernel.org Signed-off-by: Zhenhua Huang quic_zhenhuah@quicinc.com Acked-by: David Rientjes rientjes@google.com Acked-by: Harry Yoo harry.yoo@oracle.com Tested-by: Harry Yoo harry.yoo@oracle.com Acked-by: Suren Baghdasaryan surenb@google.com Link: https://patch.msgid.link/20250421075232.2165527-1-quic_zhenhuah@quicinc.com Signed-off-by: Vlastimil Babka vbabka@suse.cz (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) [surenb: fixed trivial merge conflict in alloc_tagging_slab_alloc_hook(), skipped inlining free_slab_obj_exts() as it's already inline in 6.12] Signed-off-by: Suren Baghdasaryan surenb@google.com --- mm/slub.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index c26d9cd107cc..66f86e532818 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2035,18 +2035,6 @@ static inline void free_slab_obj_exts(struct slab *slab) slab->obj_exts = 0; }
-static inline bool need_slab_obj_ext(void) -{ - if (mem_alloc_profiling_enabled()) - return true; - - /* - * CONFIG_MEMCG creates vector of obj_cgroup objects conditionally - * inside memcg_slab_post_alloc_hook. No other users for now. - */ - return false; -} - #else /* CONFIG_SLAB_OBJ_EXT */
static inline void init_slab_obj_exts(struct slab *slab) @@ -2063,11 +2051,6 @@ static inline void free_slab_obj_exts(struct slab *slab) { }
-static inline bool need_slab_obj_ext(void) -{ - return false; -} - #endif /* CONFIG_SLAB_OBJ_EXT */
#ifdef CONFIG_MEM_ALLOC_PROFILING @@ -2099,7 +2082,7 @@ prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p) static inline void alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) { - if (need_slab_obj_ext()) { + if (mem_alloc_profiling_enabled()) { struct slabobj_ext *obj_exts;
obj_exts = prepare_slab_obj_exts_hook(s, flags, object); @@ -2577,8 +2560,12 @@ static __always_inline void account_slab(struct slab *slab, int order, static __always_inline void unaccount_slab(struct slab *slab, int order, struct kmem_cache *s) { - if (memcg_kmem_online() || need_slab_obj_ext()) - free_slab_obj_exts(slab); + /* + * The slab object extensions should now be freed regardless of + * whether mem_alloc_profiling_enabled() or not because profiling + * might have been disabled after slab->obj_exts got allocated. + */ + free_slab_obj_exts(slab);
mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), -(PAGE_SIZE << order));
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues: ⚠️ Found matching upstream commit but patch is missing proper reference to it
Found matching upstream commit: be8250786ca94952a19ce87f98ad9906448bc9ef
WARNING: Author mismatch between patch and found commit: Backport author: Suren Baghdasaryansurenb@google.com Commit author: Zhenhua Huangquic_zhenhuah@quicinc.com
Status in newer kernel trees: 6.14.y | Present (different SHA1: 94107e5aed93)
Note: The patch differs from the upstream commit: --- 1: be8250786ca94 ! 1: 86ffacf03afed mm, slab: clean up slab->obj_exts always @@ Commit message Acked-by: Suren Baghdasaryan surenb@google.com Link: https://patch.msgid.link/20250421075232.2165527-1-quic_zhenhuah@quicinc.com Signed-off-by: Vlastimil Babka vbabka@suse.cz + (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) + [surenb: fixed trivial merge conflict in alloc_tagging_slab_alloc_hook(), + skipped inlining free_slab_obj_exts() as it's already inline in 6.12] + Signed-off-by: Suren Baghdasaryan surenb@google.com
## mm/slub.c ## -@@ mm/slub.c: int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, - return 0; - } - --/* Should be called only if mem_alloc_profiling_enabled() */ --static noinline void free_slab_obj_exts(struct slab *slab) -+static inline void free_slab_obj_exts(struct slab *slab) - { - struct slabobj_ext *obj_exts; - -@@ mm/slub.c: static noinline void free_slab_obj_exts(struct slab *slab) +@@ mm/slub.c: static inline void free_slab_obj_exts(struct slab *slab) slab->obj_exts = 0; }
@@ mm/slub.c: static inline void free_slab_obj_exts(struct slab *slab) #endif /* CONFIG_SLAB_OBJ_EXT */
#ifdef CONFIG_MEM_ALLOC_PROFILING -@@ mm/slub.c: __alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) +@@ mm/slub.c: prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p) static inline void alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) { -- if (need_slab_obj_ext()) -+ if (mem_alloc_profiling_enabled()) - __alloc_tagging_slab_alloc_hook(s, object, flags); - } +- if (need_slab_obj_ext()) { ++ if (mem_alloc_profiling_enabled()) { + struct slabobj_ext *obj_exts;
+ obj_exts = prepare_slab_obj_exts_hook(s, flags, object); @@ mm/slub.c: static __always_inline void account_slab(struct slab *slab, int order, static __always_inline void unaccount_slab(struct slab *slab, int order, struct kmem_cache *s) ---
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.12.y | Success | Success |
On Thu, May 8, 2025 at 4:18 PM Sasha Levin sashal@kernel.org wrote:
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues: ⚠️ Found matching upstream commit but patch is missing proper reference to it
Not sure why "patch is missing proper reference to it". I see (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) in place. Did I miss something?
Found matching upstream commit: be8250786ca94952a19ce87f98ad9906448bc9ef
WARNING: Author mismatch between patch and found commit: Backport author: Suren Baghdasaryansurenb@google.com Commit author: Zhenhua Huangquic_zhenhuah@quicinc.com
Status in newer kernel trees: 6.14.y | Present (different SHA1: 94107e5aed93)
Note: The patch differs from the upstream commit:
Yep, this is expected as I had to make changes when backporting.
1: be8250786ca94 ! 1: 86ffacf03afed mm, slab: clean up slab->obj_exts always @@ Commit message Acked-by: Suren Baghdasaryan surenb@google.com Link: https://patch.msgid.link/20250421075232.2165527-1-quic_zhenhuah@quicinc.com Signed-off-by: Vlastimil Babka vbabka@suse.cz + (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) + [surenb: fixed trivial merge conflict in alloc_tagging_slab_alloc_hook(), + skipped inlining free_slab_obj_exts() as it's already inline in 6.12]
And the changes are documented above.
+ Signed-off-by: Suren Baghdasaryan <surenb@google.com> ## mm/slub.c ## -@@ mm/slub.c: int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, - return 0; - } - --/* Should be called only if mem_alloc_profiling_enabled() */ --static noinline void free_slab_obj_exts(struct slab *slab) -+static inline void free_slab_obj_exts(struct slab *slab) - { - struct slabobj_ext *obj_exts; - -@@ mm/slub.c: static noinline void free_slab_obj_exts(struct slab *slab) +@@ mm/slub.c: static inline void free_slab_obj_exts(struct slab *slab) slab->obj_exts = 0; } @@ mm/slub.c: static inline void free_slab_obj_exts(struct slab *slab) #endif /* CONFIG_SLAB_OBJ_EXT */ #ifdef CONFIG_MEM_ALLOC_PROFILING -@@ mm/slub.c: __alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) +@@ mm/slub.c: prepare_slab_obj_exts_hook(struct kmem_cache *s, gfp_t flags, void *p) static inline void alloc_tagging_slab_alloc_hook(struct kmem_cache *s, void *object, gfp_t flags) { -- if (need_slab_obj_ext()) -+ if (mem_alloc_profiling_enabled()) - __alloc_tagging_slab_alloc_hook(s, object, flags); - } +- if (need_slab_obj_ext()) { ++ if (mem_alloc_profiling_enabled()) { + struct slabobj_ext *obj_exts; + obj_exts = prepare_slab_obj_exts_hook(s, flags, object); @@ mm/slub.c: static __always_inline void account_slab(struct slab *slab, int order, static __always_inline void unaccount_slab(struct slab *slab, int order, struct kmem_cache *s)
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.12.y | Success | Success |
On Thu, May 08, 2025 at 05:04:45PM +0000, Suren Baghdasaryan wrote:
On Thu, May 8, 2025 at 4:18 PM Sasha Levin sashal@kernel.org wrote:
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues: ⚠️ Found matching upstream commit but patch is missing proper reference to it
Not sure why "patch is missing proper reference to it". I see (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) in place. Did I miss something?
It tries to find one of the references described in the docs for submitting stuff to stable@:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#opti...
On Thu, May 8, 2025 at 5:15 PM Sasha Levin sashal@kernel.org wrote:
On Thu, May 08, 2025 at 05:04:45PM +0000, Suren Baghdasaryan wrote:
On Thu, May 8, 2025 at 4:18 PM Sasha Levin sashal@kernel.org wrote:
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues: ⚠️ Found matching upstream commit but patch is missing proper reference to it
Not sure why "patch is missing proper reference to it". I see (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) in place. Did I miss something?
It tries to find one of the references described in the docs for submitting stuff to stable@:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-3
Ah, I see now what I missed. Thanks! Would you be able to add the reference or should I repost the backports?
-- Thanks, Sasha
On Thu, May 08, 2025 at 06:14:26PM +0000, Suren Baghdasaryan wrote:
On Thu, May 8, 2025 at 5:15 PM Sasha Levin sashal@kernel.org wrote:
On Thu, May 08, 2025 at 05:04:45PM +0000, Suren Baghdasaryan wrote:
On Thu, May 8, 2025 at 4:18 PM Sasha Levin sashal@kernel.org wrote:
[ Sasha's backport helper bot ]
Hi,
Summary of potential issues: ⚠️ Found matching upstream commit but patch is missing proper reference to it
Not sure why "patch is missing proper reference to it". I see (cherry picked from commit be8250786ca94952a19ce87f98ad9906448bc9ef) in place. Did I miss something?
It tries to find one of the references described in the docs for submitting stuff to stable@:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-3
Ah, I see now what I missed. Thanks! Would you be able to add the reference or should I repost the backports?
No need, it's already in the queue for the next round of stable releases in a few hours.
greg k-h
linux-stable-mirror@lists.linaro.org