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INFO: task hung in nbd_add_socket (2)

Status: upstream: reported C repro on 2021/12/25 23:00
Reported-by: syzbot+7f26a24b2791b871bc2a@syzkaller.appspotmail.com
First crash: 1401d, last: 1147d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in nbd_add_socket (2) block 1 C error error 37 191d 1315d 0/29 upstream: reported C repro on 2022/03/21 16:06
upstream INFO: task hung in nbd_add_socket block 1 75 1357d 1436d 0/29 closed as dup on 2021/11/21 13:59
linux-4.14 INFO: task hung in nbd_add_socket 1 1 1693d 1693d 0/1 auto-closed as invalid on 2021/07/06 19:04
linux-4.19 INFO: task hung in nbd_add_socket 1 C error 11 969d 1693d 0/1 upstream: reported C repro on 2021/03/08 23:07
linux-6.1 INFO: task hung in nbd_add_socket origin:upstream 1 C error 2 185d 889d 0/3 upstream: reported C repro on 2023/05/21 19:27
upstream INFO: task can't die in blk_mq_freeze_queue_wait block 1 221 1433d 1441d 20/29 fixed on 2022/03/08 16:11
▶ ▼ Fix bisection attempts (9)
Created Duration User Patch Repo Result
2022/10/13 02:17 0m bisect fix linux-4.14.y error job log
2022/09/05 08:14 21m bisect fix linux-4.14.y OK (0) job log log
2022/08/06 07:53 21m bisect fix linux-4.14.y OK (0) job log log
2022/06/24 02:13 24m bisect fix linux-4.14.y OK (0) job log log
2022/05/25 01:48 25m bisect fix linux-4.14.y OK (0) job log log
2022/04/25 01:26 21m bisect fix linux-4.14.y OK (0) job log log
2022/03/26 01:00 26m bisect fix linux-4.14.y OK (0) job log log
2022/02/23 23:25 26m bisect fix linux-4.14.y OK (0) job log log
2022/01/24 23:00 24m bisect fix linux-4.14.y OK (0) job log log

Sample crash report:
block nbd0: shutting down sockets
INFO: task syz-executor324:7989 blocked for more than 140 seconds.
      Not tainted 4.14.259-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor324 D29824  7989   7978 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 blk_mq_freeze_queue_wait+0xf8/0x1f0 block/blk-mq.c:154
 nbd_add_socket+0x158/0x7e0 drivers/block/nbd.c:959
 __nbd_ioctl drivers/block/nbd.c:1307 [inline]
 nbd_ioctl+0x394/0xa80 drivers/block/nbd.c:1374
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1893
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7fc7a9784299
RSP: 002b:00007fc7a9731308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc7a98084e8 RCX: 00007fc7a9784299
RDX: 0000000000000004 RSI: 000000000000ab00 RDI: 0000000000000006
RBP: 00007fc7a98084e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc7a98084ec
R13: 00007fc7a97d508c R14: 64626e2f7665642f R15: 0000000000022000
INFO: task syz-executor324:7990 blocked for more than 140 seconds.
      Not tainted 4.14.259-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor324 D30088  7990   7978 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 nbd_ioctl+0x11f/0xa80 drivers/block/nbd.c:1367
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1893
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7fc7a9784299
RSP: 002b:00007fc7a9710308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc7a98084f8 RCX: 00007fc7a9784299
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000006
RBP: 00007fc7a98084f0 R08: 00007fc7a9710700 R09: 0000000000000000
R10: 00007fc7a9710700 R11: 0000000000000246 R12: 00007fc7a98084fc
R13: 00007fc7a97d508c R14: 64626e2f7665642f R15: 0000000000022000
INFO: task syz-executor324:7991 blocked for more than 140 seconds.
      Not tainted 4.14.259-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor324 D29824  7991   7978 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 nbd_ioctl+0x11f/0xa80 drivers/block/nbd.c:1367
 __blkdev_driver_ioctl block/ioctl.c:297 [inline]
 blkdev_ioctl+0x540/0x1830 block/ioctl.c:594
 block_ioctl+0xd9/0x120 fs/block_dev.c:1893
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xff0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7fc7a9784299
RSP: 002b:00007fc7a96ef308 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc7a9808508 RCX: 00007fc7a9784299
RDX: 0000000000000005 RSI: 000000000000ab07 RDI: 0000000000000007
RBP: 00007fc7a9808500 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc7a980850c
R13: 00007fc7a97d508c R14: 64626e2f7665642f R15: 0000000000022000

Showing all locks held in the system:
1 lock held by khungtaskd/1494:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8701ebf7>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
1 lock held by syz-executor324/7989:
 #0:  (&nbd->config_lock){+.+.}, at: [<ffffffff838e5acf>] nbd_ioctl+0x11f/0xa80 drivers/block/nbd.c:1367
1 lock held by syz-executor324/7990:
 #0:  (&nbd->config_lock){+.+.}, at: [<ffffffff838e5acf>] nbd_ioctl+0x11f/0xa80 drivers/block/nbd.c:1367
1 lock held by syz-executor324/7991:
 #0:  (&nbd->config_lock){+.+.}, at: [<ffffffff838e5acf>] nbd_ioctl+0x11f/0xa80 drivers/block/nbd.c:1367

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

NMI backtrace for cpu 0
CPU: 0 PID: 1494 Comm: khungtaskd Not tainted 4.14.259-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+0x1b2/0x281 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5b9/0xb40 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff8723eb8e

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/12/25 23:00 linux-4.14.y 8ee0807eedf3 6caa12e4 .config console log report syz C ci2-linux-4-14 INFO: task hung in nbd_add_socket
2022/07/07 07:52 linux-4.14.y ed2e96e11936 bff65f44 .config console log report info ci2-linux-4-14 INFO: task hung in nbd_add_socket
* Struck through repros no longer work on HEAD.