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authorMike Christie <michael.christie@oracle.com>2023-06-07 22:23:38 +0300
committerMichael S. Tsirkin <mst@redhat.com>2023-06-08 22:43:09 +0300
commit4b13cbef797048fbb525f8c635a5279e9d209d93 (patch)
tree59de4d4c9dc49411fe09d36c1390f58f08e7ad36 /drivers/vhost
parenta284f09effea1908db7985dbfb5458c9100038d8 (diff)
downloadlinux-4b13cbef797048fbb525f8c635a5279e9d209d93.tar.xz
vhost: Fix worker hangs due to missed wake up calls
We can race where we have added work to the work_list, but vhost_task_fn has passed that check but not yet set us into TASK_INTERRUPTIBLE. wake_up_process will see us in TASK_RUNNING and just return. This bug was intoduced in commit f9010dbdce91 ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression") when I moved the setting of TASK_INTERRUPTIBLE to simplfy the code and avoid get_signal from logging warnings about being in the wrong state. This moves the setting of TASK_INTERRUPTIBLE back to before we test if we need to stop the task to avoid a possible race there as well. We then have vhost_worker set TASK_RUNNING if it finds work similar to before. Fixes: f9010dbdce91 ("fork, vhost: Use CLONE_THREAD to fix freezer/ps regression") Signed-off-by: Mike Christie <michael.christie@oracle.com> Message-Id: <20230607192338.6041-3-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/vhost.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index ca1041c88c68..1f80eac5d6ae 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -341,6 +341,8 @@ static bool vhost_worker(void *data)
node = llist_del_all(&worker->work_list);
if (node) {
+ __set_current_state(TASK_RUNNING);
+
node = llist_reverse_order(node);
/* make sure flag is seen after deletion */
smp_wmb();