On Thu, Oct 17, 2019 at 02:58:53AM +0100, Al Viro wrote: > On Wed, Oct 16, 2019 at 06:47:55PM -0700, Eric Biggers wrote: > > On Wed, Oct 16, 2019 at 06:42:11PM -0700, syzbot wrote: > > > ================================================================== > > > BUG: KASAN: use-after-free in mnt_warn_timestamp_expiry+0x4a/0x250 > > > fs/namespace.c:2471 > > > Read of size 8 at addr ffff888099937328 by task syz-executor.1/18510 > > > > > > > Looks like a duplicate of this: > > > > #syz dup: KASAN: use-after-free Read in do_mount > > > > See the existing thread and proposed fix here: > > https://lkml.kernel.org/linux-fsdevel/000000000000805e5505945a234b@xxxxxxxxxx/T/#u > > FWIW, I'd go with your "move mnt_warn_timestamp_expiry() up". However, > I'd probably turn the message into something like > foofs filesystem getting mounted at /mnt/barf supports... > And s/mounted/reconfigured/ if mnt_has_parent(mnt) is already true. > > Objections? > How about the following? pr_warn("%s filesystem being %s at %s supports timestamps until %04ld (0x%llx)\n", sb->s_type->name, is_mounted(mnt) ? "remounted" : "mounted", mntpath, tm.tm_year+1900, (unsigned long long)sb->s_time_max); I think more people would understand "remounted" than "reconfigured". Also, is_mounted(mnt) seems like a better choice than mnt_has_parent(real_mount(mnt)). - Eric
