On Tue 30-04-19 04:11:44, Al Viro wrote: > On Tue, Apr 30, 2019 at 04:55:01AM +0200, Jan Kara wrote: > > > Yeah, you're right. And if we push the patch a bit further to not take > > loop_ctl_mutex for invalid ioctl number, that would fix the problem. I > > can send a fix. > > Huh? We don't take it until in lo_simple_ioctl(), and that patch doesn't > get to its call on invalid ioctl numbers. What am I missing here? Doesn't it? blkdev_ioctl() calls into __blkdev_driver_ioctl() for unrecognized ioctl numbers. That calls into lo_ioctl() in case of a loop device. lo_ioctl() calls into lo_simple_ioctl() for ioctl numbers it doesn't recognize and lo_simple_ioctl() will lock loop_ctl_mutex as you say. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
