| From | Ben Hutchings <> | Date | Sun, 08 Sep 2013 03:52:01 +0100 | Subject | [044/121] virtio: console: fix race in port_fops_open() and port unplug |
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3.2.51-rc1 review patch. If anyone has any objections, please let me know.
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From: Amit Shah <amit.shah@redhat.com>
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> --- drivers/char/virtio_console.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -798,6 +798,10 @@ static int port_fops_open(struct inode * /* 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; /*
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