On Wed, Sep 02, 2020 at 02:58:27PM +0200, Pavel Machek wrote:
Hi!
The syzbot fuzzer identified a bug in the yurex driver: It passes GFP_KERNEL as a memory-allocation flag to usb_submit_urb() at a time when its state is TASK_INTERRUPTIBLE, not TASK_RUNNING:
Yeah, and instead of fixing the bug, patch papers over it, reducing reliability of the driver in the process.
This patch changes the call to use GFP_ATOMIC instead of GFP_KERNEL.
Fixing it properly should be as simple as moving prepare_to_wait down, no?
Sigh. That never occurred to me, but of course it is right.
Acked-by: Alan Stern stern@rowland.harvard.edu
Alan Stern
Signed-off-by: Pavel Machek (CIP) pavel@denx.de
diff --git a/drivers/usb/misc/yurex.c b/drivers/usb/misc/yurex.c index 785080f79073..5fbbb57e6e95 100644 --- a/drivers/usb/misc/yurex.c +++ b/drivers/usb/misc/yurex.c @@ -489,10 +489,10 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer, } /* send the data as the control msg */
- prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE); dev_dbg(&dev->interface->dev, "%s - submit %c\n", __func__, dev->cntl_buffer[0]);
- retval = usb_submit_urb(dev->cntl_urb, GFP_ATOMIC);
- retval = usb_submit_urb(dev->cntl_urb, GFP_KERNEL);
- prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE); if (retval >= 0) timeout = schedule_timeout(YUREX_WRITE_TIMEOUT); finish_wait(&dev->waitq, &wait);
Best regards, Pavel
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html