[syzbot] INFO: task hung in scsi_remove_host

syzbot
2022-08-21T13:42:37Z

Hello,

syzbot found the following issue on:

HEAD commit: 15b3f48a4339 Merge tag 'kbuild-fixes-v6.0' of git://git.ke..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15f72c47080000
kernel config: https://syzkaller.appspot.com/x/.config?x=3b9175e0879a7749
dashboard link: https://syzkaller.appspot.com/bug?extid=bafeb834708b1bb750bc
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1503c1f3080000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11559fc3080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bafeb834708b1bb750bc@syzkaller.appspotmail.com

INFO: task kworker/1:3:3625 blocked for more than 143 seconds.
Not tainted 6.0.0-rc1-syzkaller-00399-g15b3f48a4339 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:3 state:D stack:24520 pid: 3625 ppid: 2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5182 [inline]
__schedule+0xadf/0x52b0 kernel/sched/core.c:6494
schedule+0xda/0x1b0 kernel/sched/core.c:6570
scsi_remove_host+0x348/0x440 drivers/scsi/hosts.c:199
quiesce_and_remove_host drivers/usb/storage/usb.c:867 [inline]
usb_stor_disconnect+0x115/0x260 drivers/usb/storage/usb.c:1087
usb_unbind_interface+0x1d8/0x8e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:520 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:512
__device_release_driver drivers/base/dd.c:1209 [inline]
device_release_driver_internal+0x4a1/0x700 drivers/base/dd.c:1235
bus_remove_device+0x2e3/0x590 drivers/base/bus.c:529
device_del+0x4f3/0xc80 drivers/base/core.c:3704
usb_disable_device+0x356/0x7a0 drivers/usb/core/message.c:1419
usb_disconnect.cold+0x259/0x6ed drivers/usb/core/hub.c:2235
hub_port_connect drivers/usb/core/hub.c:5197 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5497 [inline]
port_event drivers/usb/core/hub.c:5653 [inline]
hub_event+0x1f86/0x4610 drivers/usb/core/hub.c:5735
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8bf88770 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8bf88470 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/28:
#0: ffffffff8bf892c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6492
2 locks held by getty/3285:
#0: ffff8880271c8098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
#1: ffffc90002d262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef0/0x13e0 drivers/tty/n_tty.c:2177
3 locks held by udevd/3620:
#0: ffff8880247cd488 (&of->mutex){+.+.}-{3:3}, at: kernfs_file_read_iter fs/kernfs/file.c:253 [inline]
#0: ffff8880247cd488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_read_iter+0x189/0x710 fs/kernfs/file.c:300
#1: ffff888025a62008 (kn->active#86){++++}-{0:0}, at: kernfs_file_read_iter fs/kernfs/file.c:254 [inline]
#1: ffff888025a62008 (kn->active#86){++++}-{0:0}, at: kernfs_fop_read_iter+0x1ac/0x710 fs/kernfs/file.c:300
#2: ffff888145fa8190 (&dev->mutex){....}-{3:3}, at: device_lock_interruptible include/linux/device.h:840 [inline]
#2: ffff888145fa8190 (&dev->mutex){....}-{3:3}, at: read_descriptors+0x3c/0x2c0 drivers/usb/core/sysfs.c:873
5 locks held by kworker/1:3/3625:
#0: ffff8880178f4d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8880178f4d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
#0: ffff8880178f4d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
#0: ffff8880178f4d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
#0: ffff8880178f4d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
#0: ffff8880178f4d38 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
#1: ffffc9000391fda8 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
#2: ffff888021892190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#2: ffff888021892190 (&dev->mutex){....}-{3:3}, at: hub_event+0x1bc/0x4610 drivers/usb/core/hub.c:5681
#3: ffff888145fa8190 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#3: ffff888145fa8190 (&dev->mutex){....}-{3:3}, at: usb_disconnect.cold+0x43/0x6ed drivers/usb/core/hub.c:2226
#4: ffff888145e08118 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:835 [inline]
#4: ffff888145e08118 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1038 [inline]
#4: ffff888145e08118 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xa0/0x700 drivers/base/dd.c:1232

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.0.0-rc1-syzkaller-00399-g15b3f48a4339 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x46/0x14f lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x206/0x250 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0xc18/0xf50 kernel/hung_task.c:369
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3612 Comm: syz-executor262 Not tainted 6.0.0-rc1-syzkaller-00399-g15b3f48a4339 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:226 [inline]
RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:227 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4752 [inline]
RIP: 0010:__lock_acquire+0x6f0/0x56d0 kernel/locking/lockdep.c:5003
Code: 8e af 27 00 00 0f b7 53 20 66 81 e2 ff 1f 0f b7 da be 08 00 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 40 d9 8d 90 e8 50 49 69 00 <48> 0f a3 1d 18 bd 2e 0f 0f 82 3f ff ff ff 48 c7 c0 c0 d8 1a 91 48
RSP: 0018:ffffc9000383f9d8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 00000000000000a1 RCX: ffffffff815f1c20
RDX: fffffbfff211bb2b RSI: 0000000000000008 RDI: ffffffff908dd950
RBP: 0000000000000004 R08: 0000000000000000 R09: ffffffff908dd957
R10: fffffbfff211bb2a R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801f27bb00 R14: ffff88801f27c578 R15: dffffc0000000000
FS: 0000555555da6300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f926af390f1 CR3: 000000001d660000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
rcu_lock_acquire include/linux/rcupdate.h:280 [inline]
rcu_read_lock include/linux/rcupdate.h:706 [inline]
__task_pid_nr_ns+0x3d/0x4b0 kernel/pid.c:497
task_pid_nr_ns include/linux/sched.h:1557 [inline]
send_signal_locked+0x398/0x700 kernel/signal.c:1247
do_notify_parent_cldstop+0x9a5/0xa40 kernel/signal.c:2185
ptrace_stop.part.0+0x834/0xa80 kernel/signal.c:2293
ptrace_stop kernel/signal.c:2232 [inline]
ptrace_do_notify+0x215/0x2b0 kernel/signal.c:2344
ptrace_notify+0xc4/0x140 kernel/signal.c:2356
ptrace_report_syscall include/linux/ptrace.h:420 [inline]
ptrace_report_syscall_exit include/linux/ptrace.h:482 [inline]
syscall_exit_work kernel/entry/common.c:249 [inline]
syscall_exit_to_user_mode_prepare+0x129/0x280 kernel/entry/common.c:276
__syscall_exit_to_user_mode_work kernel/entry/common.c:281 [inline]
syscall_exit_to_user_mode+0x9/0x50 kernel/entry/common.c:294
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f926af2cb8a
Code: 83 ff 03 74 3b 48 83 ec 28 b8 fa ff ff ff 83 ff 02 49 89 ca 0f 44 f8 64 8b 04 25 18 00 00 00 85 c0 75 2d b8 e6 00 00 00 0f 05 <89> c2 f7 da 3d 00 f0 ff ff b8 00 00 00 00 0f 47 c2 48 83 c4 28 c3
RSP: 002b:00007ffefe88cd30 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: 0000000000000000 RBX: 000000000003da83 RCX: 00007f926af2cb8a
RDX: 00007ffefe88cd70 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000eb7 R08: 00000000000000fe R09: 00007ffefe981080
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffefe88cdac
R13: 431bde82d7b634db R14: 00007ffefe88cdd0 R15: 00007ffefe88cdb0
</TASK>

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