XFS (loop3): Invalid superblock magic number
------------[ cut here ]------------
WARNING: CPU: 0 PID: 3267 at kernel/workqueue.c:4124 destroy_workqueue+0x1d3/0x710 kernel/workqueue.c:4124
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 3267 Comm: syz-executor.3 Not tainted 4.14.209-syzkaller #0
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+0x1b2/0x283 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x20/0x4b kernel/panic.c:547
 report_bug+0x208/0x249 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x195/0x2d0 arch/x86/kernel/traps.c:295
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:964
RIP: 0010:destroy_workqueue+0x1d3/0x710 kernel/workqueue.c:4124
RSP: 0018:ffff8880512efc08 EFLAGS: 00010216
gfs2: fsid=syz:syz: Trying to join cluster "lock_nolock", "syz:syz"
RAX: 0000000000040000 RBX: ffff8880913de5c0 RCX: ffffc90007d10000
gfs2: fsid=syz:syz: Now mounting FS...
RDX: 0000000000014b28 RSI: ffffffff81379363 RDI: 0000000000000286
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000040030
R10: ffff88809c9bcb30 R11: ffff88809c9bc280 R12: ffffe8ffffd7b858
R13: ffffe8ffffd7b800 R14: ffff8880913de5e0 R15: ffffe8ffffd7b840
 xfs_destroy_mount_workqueues+0x143/0x1c0 fs/xfs/xfs_super.c:933
 xfs_fs_fill_super+0x801/0x1380 fs/xfs/xfs_super.c:1714
 mount_bdev+0x2b3/0x360 fs/super.c:1134
gfs2: fsid=syz:syz.0: journal 0 mapped with 1 extents
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
gfs2: fsid=syz:syz.0: jid=0, already locked for use
gfs2: fsid=syz:syz.0: jid=0: Looking at journal...
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
gfs2: fsid=syz:syz.0: jid=0: Done
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x46090a
gfs2: fsid=syz:syz.0: first mount done, others may mount
RSP: 002b:00007fa2d36d3a88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fa2d36d3b20 RCX: 000000000046090a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fa2d36d3ae0
RBP: 00007fa2d36d3ae0 R08: 00007fa2d36d3b20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020209b00
Kernel Offset: disabled
Rebooting in 86400 seconds..