On 05/04/18 09:19, Dmitry Vyukov wrote:
On Thu, Apr 5, 2018 at 8:34 AM, Greg KH <gre...@linuxfoundation.org> wrote:
On Wed, Apr 04, 2018 at 07:02:01PM -0700, syzbot wrote:
syzbot hit the following crash on upstream commit
3e968c9f1401088abc9a19ae6ff571644d37a355 (Wed Apr 4 21:19:24 2018 +0000)
Merge tag 'ext4_for_linus' of
syzbot dashboard link:
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5104666266304512
Raw console output:
compiler: gcc (GCC) 7.1.1 20170620
IMPORTANT: if you fix the bug, please add the following tag to the commit:
It will help syzbot understand when the bug is fixed. See footer for
If you forward the report, please keep this part and the footer.
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000003
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
------------[ cut here ]------------
kobject_add_internal failed for nodev( with -EEXIST, don't try to register
things with the same name in the same directory.
sysfs: cannot create duplicate filename '/fs/gfs2/nodev('
WARNING: CPU: 1 PID: 4473 at lib/kobject.c:238
CPU: 0 PID: 4474 Comm: syzkaller533472 Not tainted 4.16.0+ #15
Kernel panic - not syncing: panic_on_warn set ...
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
__dump_stack lib/dump_stack.c:17 [inline]
create_dir lib/kobject.c:69 [inline]
kobject_add_varg lib/kobject.c:364 [inline]
gfs2 bug, not a sysfs bug, we are correctly warning about an incorrect
usage of the api.
Then +gfs2 maintainers.
Now if we should turn this into a non-WARN message, that's a different
thing, I'll gladly take a patch for that.
If it's API usage bug in higher level code, then I think WARN is a
proper thing. We already had similar ones and they were fixed.
I'm trying to figure out what the test is doing, but it is not very
clear. At a guess I'd say that perhaps it is trying to mount multiple
filesystems with the same label? If that is the case then it is not
allowed, and it should be caught be the sysfs code and result in a
refusal to mount, which is what I think I see here. Knowing which sysfs
directory is involved would allow us to confirm, but I suspect that the
test needs altering to give each gfs2 mount a different label at an