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authorMichael S. Tsirkin <mst@redhat.com>2021-10-05 09:04:10 +0200
committerMichael S. Tsirkin <mst@redhat.com>2022-03-04 14:33:22 +0100
commit0e7174b9d5877130fec41fb4a16e0c2ee4958d44 (patch)
tree7936ce2d33c8b175413c6d257bb77853e4cb1d4f /drivers
parentvirtio: document virtio_reset_device (diff)
downloadlinux-0e7174b9d5877130fec41fb4a16e0c2ee4958d44.tar.xz
linux-0e7174b9d5877130fec41fb4a16e0c2ee4958d44.zip
virtio_console: break out of buf poll on remove
A common pattern for device reset is currently: vdev->config->reset(vdev); .. cleanup .. reset prevents new interrupts from arriving and waits for interrupt handlers to finish. However if - as is common - the handler queues a work request which is flushed during the cleanup stage, we have code adding buffers / trying to get buffers while device is reset. Not good. This was reproduced by running modprobe virtio_console modprobe -r virtio_console in a loop. Fix this up by calling virtio_break_device + flush before reset. Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1786239 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/char/virtio_console.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 2359889a35a0..e3c430539a17 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1957,6 +1957,13 @@ static void virtcons_remove(struct virtio_device *vdev)
list_del(&portdev->list);
spin_unlock_irq(&pdrvdata_lock);
+ /* Device is going away, exit any polling for buffers */
+ virtio_break_device(vdev);
+ if (use_multiport(portdev))
+ flush_work(&portdev->control_work);
+ else
+ flush_work(&portdev->config_work);
+
/* Disable interrupts for vqs */
virtio_reset_device(vdev);
/* Finish up work that's lined up */