This is a note to let you know that I've just added the patch titled
virtio: console: Don't access vqs if device was unplugged
to the 2.6.37-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
virtio-console-don-t-access-vqs-if-device-was-unplugged.patch
and it can be found in the queue-2.6.37 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From d7a62cd0332115d4c7c4689abea0d889a30d8349 Mon Sep 17 00:00:00 2001
From: Amit Shah <[email protected]>
Date: Fri, 4 Mar 2011 14:04:33 +1030
Subject: virtio: console: Don't access vqs if device was unplugged
From: Amit Shah <[email protected]>
commit d7a62cd0332115d4c7c4689abea0d889a30d8349 upstream.
If a virtio-console device gets unplugged while a port is open, a
subsequent close() call on the port accesses vqs to free up buffers.
This can lead to a crash.
The buffers are already freed up as a result of the call to
unplug_ports() from virtcons_remove(). The fix is to simply not access
vq information if port->portdev is NULL.
Reported-by: juzhang <[email protected]>
Signed-off-by: Amit Shah <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/char/virtio_console.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -387,6 +387,10 @@ static void discard_port_data(struct por
unsigned int len;
int ret;
+ if (!port->portdev) {
+ /* Device has been unplugged. vqs are already gone. */
+ return;
+ }
vq = port->in_vq;
if (port->inbuf)
buf = port->inbuf;
@@ -469,6 +473,10 @@ static void reclaim_consumed_buffers(str
void *buf;
unsigned int len;
+ if (!port->portdev) {
+ /* Device has been unplugged. vqs are already gone. */
+ return;
+ }
while ((buf = virtqueue_get_buf(port->out_vq, &len))) {
kfree(buf);
port->outvq_full = false;
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.37/virtio-console-don-t-access-vqs-if-device-was-unplugged.patch
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