INFO: task hung in sysfs_warn_dup

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a1b977b4 Linux 4.19.150
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1081da44500000
kernel config: https://syzkaller.appspot.com/x/.config?x=c14008c8da1ca4d4
dashboard link: https://syzkaller.appspot.com/bug?extid=99caffe96314cc08c512
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+99caff...@syzkaller.appspotmail.com

gfs2: fsid=syz:syz.0: jid=0, already locked for use
gfs2: fsid=syz:syz.0: jid=0: Looking at journal...
gfs2: fsid=syz:syz.0: jid=0: Done
gfs2: fsid=syz:syz.0: first mount done, others may mount
INFO: task kworker/0:2:2754 blocked for more than 140 seconds.
Not tainted 4.19.150-syzkaller #0
sysfs: cannot create duplicate filename '/fs/gfs2/syz:syz'
CPU: 0 PID: 7510 Comm: syz-executor.4 Not tainted 4.19.150-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
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+0x22c/0x33e lib/dump_stack.c:118
sysfs_warn_dup.cold+0x1c/0x2d fs/sysfs/dir.c:30
sysfs_create_dir_ns+0x234/0x290 fs/sysfs/dir.c:63
create_dir lib/kobject.c:88 [inline]
kobject_add_internal+0x296/0x9a0 lib/kobject.c:247
kobject_add_varg lib/kobject.c:382 [inline]
kobject_init_and_add+0x101/0x160 lib/kobject.c:453
gfs2_sys_fs_add+0x18e/0x440 fs/gfs2/sys.c:659
kworker/0:2 D25248 2754 2 0x80000000
fill_super+0x125b/0x2680 fs/gfs2/ops_fstype.c:1099
Workqueue: usb_hub_wq hub_event
gfs2_mount+0x4c0/0x598 fs/gfs2/ops_fstype.c:1312
mount_fs+0xa3/0x318 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799
Call Trace:
ksys_mount+0xcf/0x130 fs/namespace.c:3015
__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x8e5/0x22e0 kernel/sched/core.c:3517
do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4608aa
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 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 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f7289b7aa88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f7289b7ab20 RCX: 00000000004608aa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f7289b7aae0
RBP: 00007f7289b7aae0 R08: 00007f7289b7ab20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020047a20
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop1.
VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop2.
usb_kill_urb.part.0+0x197/0x220 drivers/usb/core/urb.c:697
usb_kill_urb+0x7c/0x90 drivers/usb/core/urb.c:692
usb_start_wait_urb+0x24f/0x2b0 drivers/usb/core/message.c:63
usb_internal_control_msg drivers/usb/core/message.c:101 [inline]
usb_control_msg+0x31c/0x4a0 drivers/usb/core/message.c:152
hub_port_init+0x8b3/0x2ea0 drivers/usb/core/hub.c:4654
hub_port_connect drivers/usb/core/hub.c:5020 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5203 [inline]
port_event drivers/usb/core/hub.c:5311 [inline]
hub_event+0x1981/0x3fc0 drivers/usb/core/hub.c:5391
process_one_work+0x796/0x14e0 kernel/workqueue.c:2155
worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
qnx6: invalid mount options.
kthread+0x33f/0x460 kernel/kthread.c:259
overlayfs: upperdir is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Showing all locks held in the system:
1 lock held by khungtaskd/1095:
qnx6: invalid mount options.
#0: 00000000ea2b9df0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x291 kernel/locking/lockdep.c:4440
5 locks held by kworker/0:2/2754:
#0: 00000000fde613bc ((wq_completion)"usb_hub_wq"){+.+.}, at: process_one_work+0x692/0x14e0 kernel/workqueue.c:2126
#1: 00000000368096f3 ((work_completion)(&hub->events)){+.+.}, at: process_one_work+0x6c8/0x14e0 kernel/workqueue.c:2130
#2: 00000000d0e52326 (&dev->mutex){....}, at: device_lock include/linux/device.h:1173 [inline]
#2: 00000000d0e52326 (&dev->mutex){....}, at: hub_event+0x10f/0x3fc0 drivers/usb/core/hub.c:5337
#3: 00000000e3ae0a1d (&port_dev->status_lock){+.+.}, at: usb_lock_port drivers/usb/core/hub.c:2977 [inline]
#3: 00000000e3ae0a1d (&port_dev->status_lock){+.+.}, at: hub_port_connect drivers/usb/core/hub.c:5019 [inline]
#3: 00000000e3ae0a1d (&port_dev->status_lock){+.+.}, at: hub_port_connect_change drivers/usb/core/hub.c:5203 [inline]
#3: 00000000e3ae0a1d (&port_dev->status_lock){+.+.}, at: port_event drivers/usb/core/hub.c:5311 [inline]
#3: 00000000e3ae0a1d (&port_dev->status_lock){+.+.}, at: hub_event+0x196c/0x3fc0 drivers/usb/core/hub.c:5391
kobject_add_internal failed for syz:syz with -EEXIST, don't try to register things with the same name in the same directory.
#4: 00000000b782fcaf (hcd->address0_mutex){+.+.}, at: hub_port_init+0x1b5/0x2ea0 drivers/usb/core/hub.c:4528
1 lock held by in:imklog/6149:
gfs2: fsid=syz:syz: error -17 adding sysfs files
#0: 00000000801e0470 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767
2 locks held by sshd/6477:
1 lock held by syz-executor.5/6511:
#0: 00000000868c50c8 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline]
#0: 00000000868c50c8 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x537/0x7b0 kernel/rcu/tree_exp.h:667
2 locks held by kworker/0:3/6994:
#0: 0000000028a6fb49 ((wq_completion)"rcu_gp"){+.+.}, at: process_one_work+0x692/0x14e0 kernel/workqueue.c:2126
VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop1.
#1: 000000005177e738 ((work_completion)(&rew.rew_work)){+.+.}, at: process_one_work+0x6c8/0x14e0 kernel/workqueue.c:2130
2 locks held by syz-executor.1/7574:
1 lock held by syz-executor.1/7579:
#0: 00000000e73f1c5b (loop_ctl_mutex){+.+.}, at: __loop_clr_fd+0x88/0xda0 drivers/block/loop.c:1080
VFS: Can't find a Minix filesystem V1 | V2 | V3 on device loop2.
2 locks held by syz-executor.2/7578:
1 lock held by syz-executor.2/7583:
#0: 00000000e73f1c5b (loop_ctl_mutex){+.+.}, at: __loop_clr_fd+0x88/0xda0 drivers/block/loop.c:1080

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1095 Comm: khungtaskd Not tainted 4.19.150-syzkaller #0
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+0x22c/0x33e lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x18/0x3d lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
watchdog+0xa62/0x1020 kernel/hung_task.c:287
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7585 Comm: syz-executor.0 Not tainted 4.19.150-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:lockdep_hardirqs_on+0x68/0x5e0 kernel/locking/lockdep.c:2848
Code: 84 6c 03 00 00 65 48 8b 1c 25 40 ee 01 00 48 8d bb 84 08 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 <48> 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 ce 03 00 00 44
RSP: 0018:ffff888030f27f08 EFLAGS: 00000807
RAX: dffffc0000000000 RBX: ffff888049ec6340 RCX: 1ffffffff142e5cc
RDX: 0000000000000000 RSI: ffffffff81774d25 RDI: ffff888049ec6bc4
RBP: ffffffff8100a441 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff896389f8 R14: 0000000000000000 R15: 0000000000000000
FS: 00007ff9ec357700(0000) GS:ffff8880ae300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00fb9b000 CR3: 00000000924de000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
do_syscall_64+0x21/0x670 arch/x86/entry/common.c:280
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4179b7
Code: 12 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 a1 18 00 00 c3 48 83 ec 08 e8 07 fa ff ff 48 89 04 24 49 89 ca b8 12 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 4d fa ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ff9ec356a20 EFLAGS: 00000293 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 000000000000051b RCX: 00000000004179b7
RDX: 0000000000000060 RSI: 0000000020032cc0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 000000002000dca0 R09: 0000000000000000
R10: 0000000000530000 R11: 0000000000000293 R12: 000000000000091c
R13: 0000000000000003 R14: 0000000000000003 R15: 0000000020007c98
overlayfs: unrecognized mount option "lowerfir=./bus" or missing value


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.