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| author | Amit Shah <amit.shah@redhat.com> | 2013-07-29 14:17:13 +0930 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-14 22:57:06 -0700 |
| commit | 9c040cbf67c54c0eb67ebdc0424cfadd3d7a2a7a (patch) | |
| tree | 6420c53f4be2a0d0bd36f878f139ac145ea9808e /drivers | |
| parent | d0bfaacabec9c87b739c31662eaa96af0d1b404c (diff) | |
| download | lwn-9c040cbf67c54c0eb67ebdc0424cfadd3d7a2a7a.tar.gz lwn-9c040cbf67c54c0eb67ebdc0424cfadd3d7a2a7a.zip | |
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>
Diffstat (limited to 'drivers')
| -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 1e10b8b4e453..23f135f65fca 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -794,6 +794,10 @@ 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; /* |