Re: [PATCH 1/2] drm/nouveau: fix stale locked mutex in nouveau_gem_ioctl_pushbuf

From: Lyude Paul
Date: Mon Mar 04 2024 - 14:30:30 EST


Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>

On Mon, 2024-03-04 at 19:31 +0100, Karol Herbst wrote:
> If VM_BIND is enabled on the client the legacy submission ioctl can't be
> used, however if a client tries to do so regardless it will return an
> error. In this case the clients mutex remained unlocked leading to a
> deadlock inside nouveau_drm_postclose or any other nouveau ioctl call.
>
> Fixes: b88baab82871 ("drm/nouveau: implement new VM_BIND uAPI")
> Cc: Danilo Krummrich <dakr@xxxxxxxxxx>
> Signed-off-by: Karol Herbst <kherbst@xxxxxxxxxx>
> ---
> drivers/gpu/drm/nouveau/nouveau_gem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
> index 49c2bcbef1299..5a887d67dc0e8 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_gem.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
> @@ -764,7 +764,7 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data,
> return -ENOMEM;
>
> if (unlikely(nouveau_cli_uvmm(cli)))
> - return -ENOSYS;
> + return nouveau_abi16_put(abi16, -ENOSYS);
>
> list_for_each_entry(temp, &abi16->channels, head) {
> if (temp->chan->chid == req->channel) {

--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat