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
Cc: stable@vger.kernel.org Fixes: 21c690a349ba ("mm: introduce slabobj_ext to support slab object extensions") 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 --- mm/slub.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index 566eb8b8282d..a98ce1426076 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2028,8 +2028,8 @@ 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) +/* Free only if slab_obj_exts(slab) */ +static inline void free_slab_obj_exts(struct slab *slab) { struct slabobj_ext *obj_exts;
@@ -2601,8 +2601,12 @@ 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));
On Mon, Apr 21, 2025 at 12:52 AM Zhenhua Huang quic_zhenhuah@quicinc.com wrote:
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
Cc: stable@vger.kernel.org Fixes: 21c690a349ba ("mm: introduce slabobj_ext to support slab object extensions") 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
mm/slub.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index 566eb8b8282d..a98ce1426076 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2028,8 +2028,8 @@ 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) +/* Free only if slab_obj_exts(slab) */
nit: the above comment is unnecessary. It's quite obvious from the code.
+static inline void free_slab_obj_exts(struct slab *slab) { struct slabobj_ext *obj_exts;
@@ -2601,8 +2601,12 @@ 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));-- 2.34.1
On 4/21/25 18:02, Suren Baghdasaryan wrote:
On Mon, Apr 21, 2025 at 12:52 AM Zhenhua Huang quic_zhenhuah@quicinc.com wrote:
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
Cc: stable@vger.kernel.org Fixes: 21c690a349ba ("mm: introduce slabobj_ext to support slab object extensions") 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
mm/slub.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c index 566eb8b8282d..a98ce1426076 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2028,8 +2028,8 @@ 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) +/* Free only if slab_obj_exts(slab) */
nit: the above comment is unnecessary. It's quite obvious from the code.
Agreed, I've removed it locally and added the patch to slab/for-next-fixes Thanks!
+static inline void free_slab_obj_exts(struct slab *slab) { struct slabobj_ext *obj_exts;
@@ -2601,8 +2601,12 @@ 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));-- 2.34.1
On Mon, Apr 21, 2025 at 03:52:32PM +0800, Zhenhua Huang wrote:
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
Please, always compile test with `make W=1`. Since CONFIG_WERROR=y this effectively breaks the build with Clang.
On Thu, Apr 24, 2025 at 07:34:29PM +0300, Andy Shevchenko wrote:
On Mon, Apr 21, 2025 at 03:52:32PM +0800, Zhenhua Huang wrote:
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
Please, always compile test with `make W=1`. Since CONFIG_WERROR=y this effectively breaks the build with Clang.
FWIW, fix has just been sent: 20250424164800.2658961-1-andriy.shevchenko@linux.intel.com
On 4/24/25 18:34, Andy Shevchenko wrote:
On Mon, Apr 21, 2025 at 03:52:32PM +0800, Zhenhua Huang wrote:
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
Please, always compile test with `make W=1`. Since CONFIG_WERROR=y this effectively breaks the build with Clang.
I don't see why, nor observe any W=1 warnings, can you be more specific? Thanks.
On Thu, Apr 24, 2025 at 06:48:46PM +0200, Vlastimil Babka wrote:
On 4/24/25 18:34, Andy Shevchenko wrote:
On Mon, Apr 21, 2025 at 03:52:32PM +0800, Zhenhua Huang wrote:
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
Please, always compile test with `make W=1`. Since CONFIG_WERROR=y this effectively breaks the build with Clang.
I don't see why, nor observe any W=1 warnings, can you be more specific? Thanks.
Specifics are in the fix I sent. Just a relatively new Clang and relatively recent enabling of warning for unused static inline functions in the C code. If you are insisting in seeing the exact kernel configuration I have, tell me where to send, I'll send it privately to avoid noise here.
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Andy Shevchenko -
Suren Baghdasaryan -
Vlastimil Babka -
Zhenhua Huang