From: "Michael S. Tsirkin" mst@redhat.com
stable inclusion from stable-v5.10.110 commit c97ffb4184f0521dfaba8be14dd76795d69e604a bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit 0e7174b9d5877130fec41fb4a16e0c2ee4958d44 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yu Liao liaoyu15@huawei.com Reviewed-by: Wei Li liwei391@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/char/virtio_console.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 673522874cec..3dd4deb60adb 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1959,6 +1959,13 @@ 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 */ vdev->config->reset(vdev); /* Finish up work that's lined up */