mm/slub.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
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));
--
2.34.1On 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. -- With Best Regards, Andy Shevchenko
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. -- With Best Regards, Andy Shevchenko
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 -- With Best Regards, Andy Shevchenko
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 2025/4/22 15:10, Vlastimil Babka wrote: >> 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! Thanks Vlastimil.
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