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authorAmit Shah <amit.shah@redhat.com>2013-07-29 14:17:13 +0930
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-08-14 22:59:08 -0700
commit60391483d53a0a9bb43e78a867173b92cf9da996 (patch)
tree8accfda6b9a9773858b2aab1f5861459137e622a
parent7b9f0c23359a5a20dccda4db14cc760625ad64c4 (diff)
downloadvexpress-lsk-60391483d53a0a9bb43e78a867173b92cf9da996.tar.gz
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/char/virtio_console.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 3beea9d478b..ffa7e46faff 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1041,6 +1041,10 @@ static int port_fops_open(struct inode *inode, struct file *filp)
/* We get the port with a kref here */
port = find_port_by_devt(cdev->dev);
+ if (!port) {
+ /* Port was unplugged before we could proceed */
+ return -ENXIO;
+ }
filp->private_data = port;
/*