Re: WARNING: ODEBUG bug in ext4_fill_super

[Dmitry Vyukov]

On Fri, Aug 30, 2019 at 12:42 PM 'Nick Desaulniers' via syzkaller-bugs
<syzkaller-bugs@xxxxxxxxxxxxxxxx> wrote:
>
> Dmitry,
> Any idea how clang-built-linux got CC'ed on this?  Is syzcaller
> running clang builds, yet?  (this looks like a GCC build)

syzbot always uses get_maintainers:

$ ./scripts/get_maintainer.pl -f fs/ext4/super.c
"Theodore Ts'o" <tytso@xxxxxxx> (maintainer:EXT4 FILE SYSTEM)
Andreas Dilger <adilger.kernel@xxxxxxxxx> (maintainer:EXT4 FILE SYSTEM)
linux-ext4@xxxxxxxxxxxxxxx (open list:EXT4 FILE SYSTEM)
linux-kernel@xxxxxxxxxxxxxxx (open list)
clang-built-linux@xxxxxxxxxxxxxxxx (open list:CLANG/LLVM BUILD SUPPORT)


> On Fri, Aug 30, 2019 at 12:39 PM syzbot
> <syzbot+0bf8ddafbdf2c46eb6f3@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit:    ed858b88 Add linux-next specific files for 20190826
> > git tree:       linux-next
> > console output: https://syzkaller.appspot.com/x/log.txt?x=14209eca600000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=ee8373cd9733e305
> > dashboard link: https://syzkaller.appspot.com/bug?extid=0bf8ddafbdf2c46eb6f3
> > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> >
> > Unfortunately, I don't have any reproducer for this crash yet.
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+0bf8ddafbdf2c46eb6f3@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > EXT4-fs (loop2): corrupt root inode, run e2fsck
> > EXT4-fs (loop2): mount failed
> > ------------[ cut here ]------------
> > ODEBUG: free active (active state 0) object type: percpu_counter hint: 0x0
> > WARNING: CPU: 0 PID: 12342 at lib/debugobjects.c:481
> > debug_print_object+0x168/0x250 lib/debugobjects.c:481
> > Kernel panic - not syncing: panic_on_warn set ...
> > CPU: 0 PID: 12342 Comm: syz-executor.2 Not tainted 5.3.0-rc6-next-20190826
> > #73
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> > Google 01/01/2011
> > Call Trace:
> >   __dump_stack lib/dump_stack.c:77 [inline]
> >   dump_stack+0x172/0x1f0 lib/dump_stack.c:113
> >   panic+0x2dc/0x755 kernel/panic.c:220
> >   __warn.cold+0x2f/0x3c kernel/panic.c:581
> >   report_bug+0x289/0x300 lib/bug.c:195
> >   fixup_bug arch/x86/kernel/traps.c:179 [inline]
> >   fixup_bug arch/x86/kernel/traps.c:174 [inline]
> >   do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
> >   do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
> >   invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
> > RIP: 0010:debug_print_object+0x168/0x250 lib/debugobjects.c:481
> > Code: dd 60 6c e6 87 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 b5 00 00 00 48
> > 8b 14 dd 60 6c e6 87 48 c7 c7 c0 61 e6 87 e8 20 31 01 fe <0f> 0b 83 05 f3
> > 67 83 06 01 48 83 c4 20 5b 41 5c 41 5d 41 5e 5d c3
> > RSP: 0018:ffff88806c9ff938 EFLAGS: 00010086
> > RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000
> > RDX: 0000000000040000 RSI: ffffffff815bd606 RDI: ffffed100d93ff19
> > RBP: ffff88806c9ff978 R08: ffff888067d48140 R09: ffffed1015d04109
> > R10: ffffed1015d04108 R11: ffff8880ae820847 R12: 0000000000000001
> > R13: ffffffff8935e800 R14: 0000000000000000 R15: ffff88806903c818
> >   __debug_check_no_obj_freed lib/debugobjects.c:963 [inline]
> >   debug_check_no_obj_freed+0x2d4/0x43f lib/debugobjects.c:994
> >   kfree+0xf8/0x2c0 mm/slab.c:3755
> >   ext4_fill_super+0x8cb/0xcc80 fs/ext4/super.c:4684
> >   mount_bdev+0x304/0x3c0 fs/super.c:1407
> >   ext4_mount+0x35/0x40 fs/ext4/super.c:6019
> >   legacy_get_tree+0x113/0x220 fs/fs_context.c:651
> >   vfs_get_tree+0x8f/0x380 fs/super.c:1482
> >   do_new_mount fs/namespace.c:2796 [inline]
> >   do_mount+0x13b3/0x1c30 fs/namespace.c:3116
> >   ksys_mount+0xdb/0x150 fs/namespace.c:3325
> >   __do_sys_mount fs/namespace.c:3339 [inline]
> >   __se_sys_mount fs/namespace.c:3336 [inline]
> >   __x64_sys_mount+0xbe/0x150 fs/namespace.c:3336
> >   do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
> >   entry_SYSCALL_64_after_hwframe+0x49/0xbe
> > RIP: 0033:0x45c2ca
> > Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 9d 8d fb ff c3 66 2e 0f
> > 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff
> > ff 0f 83 7a 8d fb ff c3 66 0f 1f 84 00 00 00 00 00
> > RSP: 002b:00007fa684517a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
> > RAX: ffffffffffffffda RBX: 00007fa684517b40 RCX: 000000000045c2ca
> > RDX: 00007fa684517ae0 RSI: 0000000020000000 RDI: 00007fa684517b00
> > RBP: 0000000000001000 R08: 00007fa684517b40 R09: 00007fa684517ae0
> > R10: 0000000000000001 R11: 0000000000000206 R12: 0000000000000003
> > R13: 00000000004c89d6 R14: 00000000004df8f8 R15: 00000000ffffffff
> > Kernel Offset: disabled
> > Rebooting in 86400 seconds..
> >
> >
> > ---
> > This bug is generated by a bot. It may contain errors.
> > See https://goo.gl/tpsmEJ for more information about syzbot.
> > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx
> >
> > syzbot will keep track of this bug report. See:
> > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> >
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>
>
>
> --
> Thanks,
> ~Nick Desaulniers
>
> --
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