From: Amit Shah <amit.shah@redhat.com>
Date: Mon, 29 Jul 2013 04:47:13 +0000 (+0930)
Subject: virtio: console: fix race in port_fops_open() and port unplug
X-Git-Tag: v3.2.51~78
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=55fa4acf3f2750cf70fbae4534b630f74397e6b9;p=pandora-kernel.git

virtio: console: fix race in port_fops_open() and port unplug

commit 671bdea2b9f210566610603ecbb6584c8a201c8c upstream.

Between open() being called and processed, the port can be unplugged.
Check if this happened, and bail out.

A simple test script to reproduce this is:

while true; do for i in $(seq 1 100); do echo $i > /dev/vport0p3; done; done;

This opens and closes the port a lot of times; unplugging the port while
this is happening triggers the bug.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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