From: Gautam Menghani gautammenghani201@gmail.com
[ Upstream commit 813ceef062b53d68f296aa3cb944b21a091fabdb ]
The function send_packet() has a race condition as follows:
func send_packet() { // do work call usb_submit_urb() mutex_unlock() wait_for_event_interruptible() <-- lock gone mutex_lock() }
func vfd_write() { mutex_lock() call send_packet() <- prev call is not completed mutex_unlock() }
When the mutex is unlocked and the function send_packet() waits for the call to complete, vfd_write() can start another call, which leads to the "URB submitted while active" warning in usb_submit_urb(). Fix this by removing the mutex_unlock() call in send_packet() and using mutex_lock_interruptible().
Link: https://syzkaller.appspot.com/bug?id=e378e6a51fbe6c5cc43e34f131cc9a315ef0337...
Fixes: 21677cfc562a ("V4L/DVB: ir-core: add imon driver") Reported-by: syzbot+0c3cb6dc05fbbdc3ad66@syzkaller.appspotmail.com Signed-off-by: Gautam Menghani gautammenghani201@gmail.com Signed-off-by: Sean Young sean@mess.org Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/rc/imon.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/media/rc/imon.c b/drivers/media/rc/imon.c index 97355e3ebdfd..72e4bb0fb71e 100644 --- a/drivers/media/rc/imon.c +++ b/drivers/media/rc/imon.c @@ -646,15 +646,14 @@ static int send_packet(struct imon_context *ictx) pr_err_ratelimited("error submitting urb(%d)\n", retval); } else { /* Wait for transmission to complete (or abort) */ - mutex_unlock(&ictx->lock); retval = wait_for_completion_interruptible( &ictx->tx.finished); if (retval) { usb_kill_urb(ictx->tx_urb); pr_err_ratelimited("task interrupted\n"); } - mutex_lock(&ictx->lock);
+ ictx->tx.busy = false; retval = ictx->tx.status; if (retval) pr_err_ratelimited("packet tx failed (%d)\n", retval); @@ -955,7 +954,8 @@ static ssize_t vfd_write(struct file *file, const char __user *buf, if (ictx->disconnected) return -ENODEV;
- mutex_lock(&ictx->lock); + if (mutex_lock_interruptible(&ictx->lock)) + return -ERESTARTSYS;
if (!ictx->dev_present_intf0) { pr_err_ratelimited("no iMON device present\n");