BUG: MAX_STACK_TRACE_ENTRIES too low! (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    1a9df9e2 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14dc2f2b200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8dcdce25ea72bedf
dashboard link: https://syzkaller.appspot.com/bug?extid=6f39a9deb697359fe520
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+6f39a9deb697359fe520@xxxxxxxxxxxxxxxxxxxxxxxxx

XFS (loop4): Invalid superblock magic number
BUG: MAX_STACK_TRACE_ENTRIES too low!
turning off the locking correctness validator.
CPU: 0 PID: 1067 Comm: syz-executor.4 Not tainted 5.1.0-rc2+ #40
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
 save_trace kernel/locking/lockdep.c:467 [inline]
 save_trace.cold+0x14/0x19 kernel/locking/lockdep.c:437
 check_prev_add.constprop.0+0x8dc/0x23c0 kernel/locking/lockdep.c:2268
 check_prevs_add kernel/locking/lockdep.c:2333 [inline]
 validate_chain kernel/locking/lockdep.c:2714 [inline]
 __lock_acquire+0x239c/0x3fb0 kernel/locking/lockdep.c:3701
 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211
 flush_workqueue+0x126/0x14c0 kernel/workqueue.c:2774
 drain_workqueue+0x1b4/0x470 kernel/workqueue.c:2939
 destroy_workqueue+0x21/0x700 kernel/workqueue.c:4320
 xfs_destroy_mount_workqueues+0xc5/0x1c0 fs/xfs/xfs_super.c:904
 xfs_fs_fill_super+0x8e9/0x1670 fs/xfs/xfs_super.c:1786
 mount_bdev+0x307/0x3c0 fs/super.c:1346
 xfs_fs_mount+0x35/0x40 fs/xfs/xfs_super.c:1834
 legacy_get_tree+0xf2/0x200 fs/fs_context.c:584
 vfs_get_tree+0x123/0x450 fs/super.c:1481
 do_new_mount fs/namespace.c:2622 [inline]
 do_mount+0x1436/0x2c40 fs/namespace.c:2942
 ksys_mount+0xdb/0x150 fs/namespace.c:3151
 __do_sys_mount fs/namespace.c:3165 [inline]
 __se_sys_mount fs/namespace.c:3162 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3162
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ac7a
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 2d 8e 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 0a 8e fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f5a0187aa88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f5a0187ab40 RCX: 000000000045ac7a
RDX: 00007f5a0187aae0 RSI: 00000000200006c0 RDI: 00007f5a0187ab00
RBP: 0000000000000000 R08: 00007f5a0187ab40 R09: 00007f5a0187aae0
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000003
R13: 00000000004c6bd2 R14: 00000000004dc5b0 R15: 00000000ffffffff


---
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.