* [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings
@ 2025-09-30 6:38 ranxiaokai627
2025-09-30 8:42 ` Harry Yoo
2025-10-03 7:51 ` Vlastimil Babka
0 siblings, 2 replies; 4+ messages in thread
From: ranxiaokai627 @ 2025-09-30 6:38 UTC (permalink / raw)
To: vbabka, akpm, cl, rientjes, roman.gushchin, harry.yoo, ast
Cc: linux-kernel, linux-mm, ran.xiaokai, ranxiaokai627
From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
In slab_post_alloc_hook(), kmemleak check is skipped when
gfpflags_allow_spinning() returns false since commit 13d872ade8be
("slab: Introduce kmalloc_nolock() and kfree_nolock().").
Therefore, unconditionally calling kmemleak_not_leak() in
alloc_slab_obj_exts() would trigger the following warning:
kmemleak: Trying to color unknown object at 0xffff8881057f5000 as Grey
Call Trace:
alloc_slab_obj_exts+0x1b5/0x370
__alloc_tagging_slab_alloc_hook+0x9f/0x2d0
__kmalloc_cache_noprof+0x1c4/0x5c0
__set_page_owner+0x10d/0x1c0
post_alloc_hook+0x84/0xf0
get_page_from_freelist+0x73b/0x1380
__alloc_frozen_pages_noprof+0x110/0x2c0
alloc_pages_mpol+0x44/0x140
alloc_slab_page+0xac/0x150
allocate_slab+0x78/0x3a0
___slab_alloc+0x76b/0xed0
__slab_alloc.constprop.0+0x5a/0xb0
Add the allow_spin check in alloc_slab_obj_exts() to
eliminate the above warning.
Fixes: 13d872ade8be ("slab: Introduce kmalloc_nolock() and kfree_nolock().")
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
---
mm/slub.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/slub.c b/mm/slub.c
index 09cbe580842c..a76275f4870a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2145,7 +2145,8 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
return 0;
}
- kmemleak_not_leak(vec);
+ if (allow_spin)
+ kmemleak_not_leak(vec);
return 0;
}
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings
2025-09-30 6:38 [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings ranxiaokai627
@ 2025-09-30 8:42 ` Harry Yoo
2025-09-30 11:04 ` Alexei Starovoitov
2025-10-03 7:51 ` Vlastimil Babka
1 sibling, 1 reply; 4+ messages in thread
From: Harry Yoo @ 2025-09-30 8:42 UTC (permalink / raw)
To: ranxiaokai627
Cc: vbabka, akpm, cl, rientjes, roman.gushchin, ast, linux-kernel,
linux-mm, ran.xiaokai
On Tue, Sep 30, 2025 at 06:38:31AM +0000, ranxiaokai627@163.com wrote:
> From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>
> In slab_post_alloc_hook(), kmemleak check is skipped when
> gfpflags_allow_spinning() returns false since commit 13d872ade8be
> ("slab: Introduce kmalloc_nolock() and kfree_nolock().").
> Therefore, unconditionally calling kmemleak_not_leak() in
> alloc_slab_obj_exts() would trigger the following warning:
Good catch.
> kmemleak: Trying to color unknown object at 0xffff8881057f5000 as Grey
> Call Trace:
> alloc_slab_obj_exts+0x1b5/0x370
> __alloc_tagging_slab_alloc_hook+0x9f/0x2d0
> __kmalloc_cache_noprof+0x1c4/0x5c0
> __set_page_owner+0x10d/0x1c0
> post_alloc_hook+0x84/0xf0
> get_page_from_freelist+0x73b/0x1380
> __alloc_frozen_pages_noprof+0x110/0x2c0
> alloc_pages_mpol+0x44/0x140
> alloc_slab_page+0xac/0x150
> allocate_slab+0x78/0x3a0
> ___slab_alloc+0x76b/0xed0
> __slab_alloc.constprop.0+0x5a/0xb0
>
> Add the allow_spin check in alloc_slab_obj_exts() to
> eliminate the above warning.
>
> Fixes: 13d872ade8be ("slab: Introduce kmalloc_nolock() and kfree_nolock().")
The commit hash in the tag and commit message will be adjusted after -rc1
when picking up this patch.
> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> ---
Looks good to me,
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
--
Cheers,
Harry / Hyeonggon
> mm/slub.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 09cbe580842c..a76275f4870a 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2145,7 +2145,8 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
> return 0;
> }
>
> - kmemleak_not_leak(vec);
> + if (allow_spin)
> + kmemleak_not_leak(vec);
> return 0;
> }
>
> --
> 2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings
2025-09-30 8:42 ` Harry Yoo
@ 2025-09-30 11:04 ` Alexei Starovoitov
0 siblings, 0 replies; 4+ messages in thread
From: Alexei Starovoitov @ 2025-09-30 11:04 UTC (permalink / raw)
To: Harry Yoo
Cc: ranxiaokai627, Vlastimil Babka, Andrew Morton, cl,
David Rientjes, Roman Gushchin, Alexei Starovoitov, LKML,
linux-mm, ran.xiaokai
On Tue, Sep 30, 2025 at 10:43 AM Harry Yoo <harry.yoo@oracle.com> wrote:
>
> On Tue, Sep 30, 2025 at 06:38:31AM +0000, ranxiaokai627@163.com wrote:
> > From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> >
> > In slab_post_alloc_hook(), kmemleak check is skipped when
> > gfpflags_allow_spinning() returns false since commit 13d872ade8be
> > ("slab: Introduce kmalloc_nolock() and kfree_nolock().").
> > Therefore, unconditionally calling kmemleak_not_leak() in
> > alloc_slab_obj_exts() would trigger the following warning:
>
> Good catch.
>
> > kmemleak: Trying to color unknown object at 0xffff8881057f5000 as Grey
> > Call Trace:
> > alloc_slab_obj_exts+0x1b5/0x370
> > __alloc_tagging_slab_alloc_hook+0x9f/0x2d0
> > __kmalloc_cache_noprof+0x1c4/0x5c0
> > __set_page_owner+0x10d/0x1c0
> > post_alloc_hook+0x84/0xf0
> > get_page_from_freelist+0x73b/0x1380
> > __alloc_frozen_pages_noprof+0x110/0x2c0
> > alloc_pages_mpol+0x44/0x140
> > alloc_slab_page+0xac/0x150
> > allocate_slab+0x78/0x3a0
> > ___slab_alloc+0x76b/0xed0
> > __slab_alloc.constprop.0+0x5a/0xb0
> >
> > Add the allow_spin check in alloc_slab_obj_exts() to
> > eliminate the above warning.
> >
> > Fixes: 13d872ade8be ("slab: Introduce kmalloc_nolock() and kfree_nolock().")
>
> The commit hash in the tag and commit message will be adjusted after -rc1
> when picking up this patch.
>
> > Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
> > ---
>
> Looks good to me,
> Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Makes sense to me as well:
Acked-by: Alexei Starovoitov <ast@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings
2025-09-30 6:38 [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings ranxiaokai627
2025-09-30 8:42 ` Harry Yoo
@ 2025-10-03 7:51 ` Vlastimil Babka
1 sibling, 0 replies; 4+ messages in thread
From: Vlastimil Babka @ 2025-10-03 7:51 UTC (permalink / raw)
To: ranxiaokai627, akpm, cl, rientjes, roman.gushchin, harry.yoo, ast
Cc: linux-kernel, linux-mm, ran.xiaokai
On 9/30/25 08:38, ranxiaokai627@163.com wrote:
> From: Ran Xiaokai <ran.xiaokai@zte.com.cn>
>
> In slab_post_alloc_hook(), kmemleak check is skipped when
> gfpflags_allow_spinning() returns false since commit 13d872ade8be
> ("slab: Introduce kmalloc_nolock() and kfree_nolock().").
> Therefore, unconditionally calling kmemleak_not_leak() in
> alloc_slab_obj_exts() would trigger the following warning:
>
> kmemleak: Trying to color unknown object at 0xffff8881057f5000 as Grey
> Call Trace:
> alloc_slab_obj_exts+0x1b5/0x370
> __alloc_tagging_slab_alloc_hook+0x9f/0x2d0
> __kmalloc_cache_noprof+0x1c4/0x5c0
> __set_page_owner+0x10d/0x1c0
> post_alloc_hook+0x84/0xf0
> get_page_from_freelist+0x73b/0x1380
> __alloc_frozen_pages_noprof+0x110/0x2c0
> alloc_pages_mpol+0x44/0x140
> alloc_slab_page+0xac/0x150
> allocate_slab+0x78/0x3a0
> ___slab_alloc+0x76b/0xed0
> __slab_alloc.constprop.0+0x5a/0xb0
>
> Add the allow_spin check in alloc_slab_obj_exts() to
> eliminate the above warning.
>
> Fixes: 13d872ade8be ("slab: Introduce kmalloc_nolock() and kfree_nolock().")
Updated commit hash (also above)
> Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Added to slab/for-next-fixes, thanks!
> ---
> mm/slub.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 09cbe580842c..a76275f4870a 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2145,7 +2145,8 @@ int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
> return 0;
> }
>
> - kmemleak_not_leak(vec);
> + if (allow_spin)
> + kmemleak_not_leak(vec);
> return 0;
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-09-30 6:38 [PATCH] slab: Add allow_spin check to eliminate kmemleak warnings ranxiaokai627
2025-09-30 8:42 ` Harry Yoo
2025-09-30 11:04 ` Alexei Starovoitov
2025-10-03 7:51 ` Vlastimil Babka
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