* [PATCH] mm/vmalloc: Take vmap_purge_lock in shrinker
@ 2026-04-13 19:26 Uladzislau Rezki (Sony)
2026-04-14 7:20 ` Baoquan He
0 siblings, 1 reply; 2+ messages in thread
From: Uladzislau Rezki (Sony) @ 2026-04-13 19:26 UTC (permalink / raw)
To: linux-mm, Andrew Morton
Cc: Baoquan He, LKML, Uladzislau Rezki, stable, chenyichong
decay_va_pool_node() can be invoked concurrently from two paths:
__purge_vmap_area_lazy() when pools are being purged, and the
shrinker via vmap_node_shrink_scan().
However, decay_va_pool_node() is not safe to run concurrently,
and the shrinker path currently lacks serialization, leading
to races and possible leaks.
Protect decay_va_pool_node() by taking vmap_purge_lock in the
shrinker path to ensure serialization with purge users.
Cc: stable@vger.kernel.org
Cc: chenyichong <chenyichong@uniontech.com>
Fixes: 7679ba6b36db ("mm: vmalloc: add a shrinker to drain vmap pools")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
mm/vmalloc.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 61caa55a4402..676851d5cfe7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -5416,6 +5416,7 @@ vmap_node_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
{
struct vmap_node *vn;
+ guard(mutex)(&vmap_purge_lock);
for_each_vmap_node(vn)
decay_va_pool_node(vn, true);
--
2.47.3
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] mm/vmalloc: Take vmap_purge_lock in shrinker
2026-04-13 19:26 [PATCH] mm/vmalloc: Take vmap_purge_lock in shrinker Uladzislau Rezki (Sony)
@ 2026-04-14 7:20 ` Baoquan He
0 siblings, 0 replies; 2+ messages in thread
From: Baoquan He @ 2026-04-14 7:20 UTC (permalink / raw)
To: Uladzislau Rezki (Sony)
Cc: linux-mm, Andrew Morton, Baoquan He, LKML, stable, chenyichong
On 04/13/26 at 09:26pm, Uladzislau Rezki (Sony) wrote:
> decay_va_pool_node() can be invoked concurrently from two paths:
> __purge_vmap_area_lazy() when pools are being purged, and the
> shrinker via vmap_node_shrink_scan().
>
> However, decay_va_pool_node() is not safe to run concurrently,
> and the shrinker path currently lacks serialization, leading
> to races and possible leaks.
>
> Protect decay_va_pool_node() by taking vmap_purge_lock in the
> shrinker path to ensure serialization with purge users.
>
> Cc: stable@vger.kernel.org
> Cc: chenyichong <chenyichong@uniontech.com>
> Fixes: 7679ba6b36db ("mm: vmalloc: add a shrinker to drain vmap pools")
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
> mm/vmalloc.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 61caa55a4402..676851d5cfe7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -5416,6 +5416,7 @@ vmap_node_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
> {
> struct vmap_node *vn;
>
> + guard(mutex)(&vmap_purge_lock);
> for_each_vmap_node(vn)
> decay_va_pool_node(vn, true);
LGTM,
Reviewed-by: Baoquan He <baoquan.he@linux.dev>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-04-14 7:20 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-04-13 19:26 [PATCH] mm/vmalloc: Take vmap_purge_lock in shrinker Uladzislau Rezki (Sony)
2026-04-14 7:20 ` Baoquan He
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox