From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Sasha Levin <sashal@kernel.org>,
amit@kernel.org, gregkh@linuxfoundation.org,
virtualization@lists.linux-foundation.org
Subject: [PATCH AUTOSEL 4.9 1/2] virtio_console: break out of buf poll on remove
Date: Wed, 16 Mar 2022 10:19:07 -0400 [thread overview]
Message-ID: <20220316141908.248848-1-sashal@kernel.org> (raw)
From: "Michael S. Tsirkin" <mst@redhat.com>
[ 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>
---
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 2632b0fdb1b5..a6b6dc204c1f 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -2004,6 +2004,13 @@ 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 */
--
2.34.1
next reply other threads:[~2022-03-16 14:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-16 14:19 Sasha Levin [this message]
2022-03-16 14:19 ` [PATCH AUTOSEL 4.9 2/2] ethernet: sun: Free the coherent when failing in probing Sasha Levin
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