On Tue, Dec 11, 2018 at 06:36:19PM +0000, Al Viro wrote: > On Tue, Dec 11, 2018 at 06:24:23PM +0100, Jan Kara wrote: > > Readers of /proc/mounts (and similar files) are currently unprotected > > from concurrently running remount on the filesystem they are reporting. > > This can not only result in bogus reported information but also in > > confusion in filesystems ->show_options callbacks resulting in > > use-after-free issues or similar (for example ext4 handling of quota > > file names is prone to such races). > > > > Fix the problem by protecting showing of mount information with > > sb->s_umount semaphore. > > Umm... Which tree is it against and what exactly does your hold_sb() do? D'oh... I need more coffee. Nevermind.
