| Message ID | 1376606874-22128-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index ff015e7..4e848c8 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -1047,6 +1047,10 @@ 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; /*
This is a note to let you know that I have just added a patch titled virtio: console: fix race in port_fops_open() and port unplug to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.7. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 4d5f8bc468ba5e5e9d95a440b1a8f180cd5d369a Mon Sep 17 00:00:00 2001 From: Amit Shah <amit.shah@redhat.com> Date: Mon, 29 Jul 2013 14:17:13 +0930 Subject: 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: Kamal Mostafa <kamal@canonical.com> --- drivers/char/virtio_console.c | 4 ++++ 1 file changed, 4 insertions(+) -- 1.8.1.2