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 <st...@rowland.harvard.edu> Alan Stern > Signed-off-by: Pavel Machek (CIP) <pa...@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
