From: Michael S. Tsirkin Date: Tue, 5 Oct 2021 07:04:10 +0000 (-0400) Subject: virtio_console: break out of buf poll on remove X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ce1a7ed741357c08c520a44734afb51567fb0b07;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git virtio_console: break out of buf poll on remove [ 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 Signed-off-by: Sasha Levin --- diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 0fb3a8e62e62..2140d401523f 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -2001,6 +2001,13 @@ 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 */