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authorAmit Shah <amit.shah@redhat.com>2013-07-29 08:47:13 +0400
committerRusty Russell <rusty@rustcorp.com.au>2013-07-29 09:13:55 +0400
commit671bdea2b9f210566610603ecbb6584c8a201c8c (patch)
tree9fcd2e27784b670fd474487eb3c2707ba88ec804
parent057b82be3ca3d066478e43b162fc082930a746c9 (diff)
downloadlinux-671bdea2b9f210566610603ecbb6584c8a201c8c.tar.xz
virtio: console: fix race in port_fops_open() and port unplug
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. CC: <stable@vger.kernel.org> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-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 3beea9d478bc..ffa7e46faff9 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;
/*