diff options
| author | Amit Shah <amit.shah@redhat.com> | 2013-07-29 14:17:13 +0930 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-14 22:55:16 -0700 |
| commit | 6c17607b4149b82da3cabffca74c2cdfb8479bb1 (patch) | |
| tree | 4ddd4dd62e1e0a56171023c6840a49610b8c4ddb | |
| parent | e3a5a432070dcebaffee8f9af193f99471280ea9 (diff) | |
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.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index a21d6d22998a..08570ef3c9fd 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -786,6 +786,10 @@ 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; /* |