R10: 0000000000800000 R11: 0000000000000217 R12: 6c6261746b636f6c
R13: 746f72706b636f6c R14: 0030656c69662f2e R15: 0000000000000004
------------[ cut here ]------------
gfs2: fsid=user.: Trying to join cluster "lock_nolock", "user."
kobject_add_internal failed for user. with -EEXIST, don't try to register things with the same name in the same directory.
WARNING: CPU: 0 PID: 4490 at lib/kobject.c:238 kobject_add_internal+0x8e0/0xba0 lib/kobject.c:236
gfs2: fsid=user.: Now mounting FS...
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 4490 Comm: syzkaller869138 Not tainted 4.16.0+ #3
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+0x1b9/0x294 lib/dump_stack.c:113
sysfs: cannot create duplicate filename '/fs/gfs2/user.'
 panic+0x22f/0x4de kernel/panic.c:184
 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536
 report_bug+0x252/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:991
RIP: 0010:kobject_add_internal+0x8e0/0xba0 lib/kobject.c:236
RSP: 0018:ffff8801acec7480 EFLAGS: 00010286
RAX: 000000000000007a RBX: ffff8801ad04d1d0 RCX: 1ffff100359c19e3
RDX: 0000000000000000 RSI: ffffffff815fa5a1 RDI: 0000000000000293
RBP: ffff8801acec7578 R08: ffff8801ace0cef8 R09: 0000000000000006
R10: ffff8801ace0c6c0 R11: 0000000000000000 R12: 00000000ffffffef
R13: ffff8801d3a02948 R14: 1ffff100359d8e9a R15: ffff8801d3a02900
 kobject_add_varg lib/kobject.c:364 [inline]
 kobject_init_and_add+0xed/0x130 lib/kobject.c:435
 gfs2_sys_fs_add+0x1ff/0x500 fs/gfs2/sys.c:652
 fill_super+0x8c9/0x1a40 fs/gfs2/ops_fstype.c:1118
 gfs2_mount+0x5e6/0x712 fs/gfs2/ops_fstype.c:1321
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 SYSC_mount fs/namespace.c:3077 [inline]
 SyS_mount+0x35/0x50 fs/namespace.c:3074
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x44327a
RSP: 002b:00007ffdfe982d48 EFLAGS: 00000217 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000044327a
RDX: 00000000200000c0 RSI: 0000000020000100 RDI: 00007ffdfe982d60
RBP: 0000000020000198 R08: 0000000020001480 R09: 000000000000000a
R10: 0000000000800000 R11: 0000000000000217 R12: 6c6261746b636f6c
R13: 746f72706b636f6c R14: 0030656c69662f2e R15: 0000000000000004
CPU: 1 PID: 4488 Comm: syzkaller869138 Not tainted 4.16.0+ #3
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+0x1b9/0x294 lib/dump_stack.c:113
 sysfs_warn_dup.cold.3+0x1c/0x2b fs/sysfs/dir.c:30
 sysfs_create_dir_ns+0x184/0x1d0 fs/sysfs/dir.c:58
 create_dir lib/kobject.c:69 [inline]
 kobject_add_internal+0x353/0xba0 lib/kobject.c:228
 kobject_add_varg lib/kobject.c:364 [inline]
 kobject_init_and_add+0xed/0x130 lib/kobject.c:435
 gfs2_sys_fs_add+0x1ff/0x500 fs/gfs2/sys.c:652
 fill_super+0x8c9/0x1a40 fs/gfs2/ops_fstype.c:1118
 gfs2_mount+0x5e6/0x712 fs/gfs2/ops_fstype.c:1321
 mount_fs+0xae/0x328 fs/super.c:1268
 vfs_kern_mount.part.34+0xd4/0x4d0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:1027 [inline]
 do_new_mount fs/namespace.c:2517 [inline]
 do_mount+0x564/0x3070 fs/namespace.c:2847
 ksys_mount+0x12d/0x140 fs/namespace.c:3063
 SYSC_mount fs/namespace.c:3077 [inline]
 SyS_mount+0x35/0x50 fs/namespace.c:3074
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x44327a
RSP: 002b:00007ffdfe982d48 EFLAGS: 00000217 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000044327a
RDX: 00000000200000c0 RSI: 0000000020000100 RDI: 00007ffdfe982d60
RBP: 0000000020000198 R08: 0000000020001480 R09: 000000000000000a
R10: 0000000000800000 R11: 0000000000000217 R12: 6c6261746b636f6c
R13: 746f72706b636f6c R14: 0030656c69662f2e R15: 0000000000000004
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..