[Devel] [PATCH VZ9] fs/fuse kio: fix lock leak in pcs_cs_find_create()

[Alexey Kuznetsov]

Ack!

On Mon, Dec 8, 2025 at 5:26 PM Liu Kui <kui.liu at virtuozzo.com> wrote:
>
> In pcs_cs_find_create(), when __lookup_cs() finds an existing cs
> during the creation path, cs->lock is acquired but not released
> before calling pcs_cs_destroy(cs) and jumping to 'again'.
>
> This lock leak can trigger "BUG: workqueue leaked lock or atomic"
> errors when called from the workqueue function fuse_complete_map_work().
> Holding a spin_lock makes the kworker unschedulable, which violates
> workqueue execution requirements.
>
> Fixes: commit "fs: fuse: pcs: implement dislog"
> https://virtuozzo.atlassian.net/browse/VSTOR-120551
>
> Signed-off-by: Liu Kui <kui.liu at virtuozzo.com>
> ---
>  fs/fuse/kio/pcs/pcs_cs.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/fs/fuse/kio/pcs/pcs_cs.c b/fs/fuse/kio/pcs/pcs_cs.c
> index 275fc8bd218d..8f4011f2afd3 100644
> --- a/fs/fuse/kio/pcs/pcs_cs.c
> +++ b/fs/fuse/kio/pcs/pcs_cs.c
> @@ -253,6 +253,7 @@ struct pcs_cs *pcs_cs_find_create(struct pcs_cs_set *csset, PCS_NODE_ID_T *id, P
>         if (__lookup_cs(csset, id->val)) {
>                 spin_unlock(&csset->lock);
>                 cs->is_dead = 1;
> +               spin_unlock(&cs->lock);
>                 pcs_cs_destroy(cs);
>                 goto again;
>         }
> --
> 2.39.5 (Apple Git-154)