Messages in this thread |  | | From | Dmitry Vyukov <> | Date | Thu, 5 Apr 2018 10:19:50 +0200 | Subject | Re: WARNING: kobject bug in sysfs_warn_dup |
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On Thu, Apr 5, 2018 at 8:34 AM, Greg KH <gregkh@linuxfoundation.org> wrote: > On Wed, Apr 04, 2018 at 07:02:01PM -0700, syzbot wrote: >> Hello, >> >> syzbot hit the following crash on upstream commit >> 3e968c9f1401088abc9a19ae6ff571644d37a355 (Wed Apr 4 21:19:24 2018 +0000) >> Merge tag 'ext4_for_linus' of >> git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 >> syzbot dashboard link: >> https://syzkaller.appspot.com/bug?extid=ff87a28e665c163aa7f5 >> >> C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5104666266304512 >> syzkaller reproducer: >> https://syzkaller.appspot.com/x/repro.syz?id=5683447737614336 >> Raw console output: >> https://syzkaller.appspot.com/x/log.txt?id=5104818200772608 >> Kernel config: >> https://syzkaller.appspot.com/x/.config?id=9118669095563550941 >> compiler: gcc (GCC) 7.1.1 20170620 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+ff87a28e665c163aa7f5@syzkaller.appspotmail.com >> It will help syzbot understand when the bug is fixed. See footer for >> details. >> 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 >> kobject_add_internal+0x8d4/0xbc0 lib/kobject.c:235 >> 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 >> Google 01/01/2011 >> Call Trace: >> __dump_stack lib/dump_stack.c:17 [inline] >> dump_stack+0x1a7/0x27d lib/dump_stack.c:53 >> sysfs_warn_dup+0x83/0xa0 fs/sysfs/dir.c:30 >> sysfs_create_dir_ns+0x178/0x1d0 fs/sysfs/dir.c:58 >> create_dir lib/kobject.c:69 [inline] >> kobject_add_internal+0x335/0xbc0 lib/kobject.c:227 >> kobject_add_varg lib/kobject.c:364 [inline] >> kobject_init_and_add+0xf9/0x150 lib/kobject.c:436 >> gfs2_sys_fs_add+0x1ff/0x580 fs/gfs2/sys.c:652 >> fill_super+0x86f/0x1d70 fs/gfs2/ops_fstype.c:1118 >> gfs2_mount+0x587/0x6e0 fs/gfs2/ops_fstype.c:1321 > > 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.
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