Lee Jones
2022-Mar-03 15:19 UTC
[PATCH 1/1] vhost: Provide a kernel warning if mutex is held whilst clean-up in progress
All workers/users should be halted before any clean-up should take place.
Suggested-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Lee Jones <lee.jones at linaro.org>
---
drivers/vhost/vhost.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index bbaff6a5e21b8..d935d2506963f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -693,6 +693,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
int i;
for (i = 0; i < dev->nvqs; ++i) {
+ /* Ideally all workers should be stopped prior to clean-up */
+ WARN_ON(mutex_is_locked(&dev->vqs[i]->mutex));
+
mutex_lock(&dev->vqs[i]->mutex);
if (dev->vqs[i]->error_ctx)
eventfd_ctx_put(dev->vqs[i]->error_ctx);
--
2.35.1.574.g5d30c73bfb-goog
Leon Romanovsky
2022-Mar-03 19:14 UTC
[PATCH 1/1] vhost: Provide a kernel warning if mutex is held whilst clean-up in progress
On Thu, Mar 03, 2022 at 03:19:29PM +0000, Lee Jones wrote:> All workers/users should be halted before any clean-up should take place. > > Suggested-by: Michael S. Tsirkin <mst at redhat.com> > Signed-off-by: Lee Jones <lee.jones at linaro.org> > --- > drivers/vhost/vhost.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index bbaff6a5e21b8..d935d2506963f 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -693,6 +693,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > int i; > > for (i = 0; i < dev->nvqs; ++i) { > + /* Ideally all workers should be stopped prior to clean-up */ > + WARN_ON(mutex_is_locked(&dev->vqs[i]->mutex)); > + > mutex_lock(&dev->vqs[i]->mutex);I know nothing about vhost, but this construction and patch looks strange to me. If all workers were stopped, you won't need mutex_lock(). The mutex_lock here suggests to me that workers can still run here. Thanks> if (dev->vqs[i]->error_ctx) > eventfd_ctx_put(dev->vqs[i]->error_ctx); > -- > 2.35.1.574.g5d30c73bfb-goog >