syzbot


INFO: task hung in tipc_exit_net (2)

Status: auto-closed as invalid on 2022/04/19 05:05
Reported-by: syzbot+3cd928f51d515eb511fe@syzkaller.appspotmail.com
First crash: 203d, last: 189d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in tipc_exit_net 8 414d 500d 0/1 auto-closed as invalid on 2021/09/06 01:04
linux-4.19 INFO: task hung in tipc_exit_net C 188 8d02h 584d 0/1 upstream: reported C repro on 2020/11/20 02:47
upstream INFO: task hung in tipc_exit_net 2 660d 663d 0/22 auto-closed as invalid on 2020/12/03 19:41

Sample crash report:
Bluetooth: hci2 command 0x0419 tx timeout
Bluetooth: hci2 command 0x0409 tx timeout
Bluetooth: hci2 command 0x041b tx timeout
Bluetooth: hci2 command 0x040f tx timeout
Bluetooth: hci2 command 0x0419 tx timeout
INFO: task kworker/u4:4:2862 blocked for more than 140 seconds.
      Not tainted 4.14.258-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:4    D26088  2862      2 0x80000000
Workqueue: netns cleanup_net
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_timeout+0x80a/0xe90 kernel/time/timer.c:1724
 do_wait_for_common kernel/sched/completion.c:91 [inline]
 __wait_for_common kernel/sched/completion.c:112 [inline]
 wait_for_common+0x272/0x430 kernel/sched/completion.c:123
 flush_workqueue+0x3ce/0x1310 kernel/workqueue.c:2677
 flush_scheduled_work include/linux/workqueue.h:578 [inline]
 tipc_exit_net+0x38/0x60 net/tipc/core.c:96
 ops_exit_list+0xa5/0x150 net/core/net_namespace.c:142
 cleanup_net+0x3b3/0x840 net/core/net_namespace.c:485
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Showing all locks held in the system:
3 locks held by kworker/0:0/3:
 #0:  ("events"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((&smc->tcp_listen_work)){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_clcsock_accept net/smc/af_smc.c:600 [inline]
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_tcp_listen_work+0x6ac/0xb80 net/smc/af_smc.c:935
1 lock held by khungtaskd/1533:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8701ebe7>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
3 locks held by kworker/u4:4/2862:
 #0:  ("%s""netns"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  (net_cleanup_work){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (net_mutex){+.+.}, at: [<ffffffff85c1cd70>] cleanup_net+0x110/0x840 net/core/net_namespace.c:451
3 locks held by kworker/1:2/3624:
 #0:  ("events"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((&smc->tcp_listen_work)){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_clcsock_accept net/smc/af_smc.c:600 [inline]
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_tcp_listen_work+0x6ac/0xb80 net/smc/af_smc.c:935
3 locks held by kworker/0:2/4315:
 #0:  ("events"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((&smc->tcp_listen_work)){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_clcsock_accept net/smc/af_smc.c:600 [inline]
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_tcp_listen_work+0x6ac/0xb80 net/smc/af_smc.c:935
3 locks held by kworker/0:3/7977:
 #0:  ("events"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((&smc->tcp_listen_work)){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_clcsock_accept net/smc/af_smc.c:600 [inline]
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_tcp_listen_work+0x6ac/0xb80 net/smc/af_smc.c:935
3 locks held by kworker/1:3/8986:
 #0:  ("events"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((&smc->tcp_listen_work)){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_clcsock_accept net/smc/af_smc.c:600 [inline]
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_tcp_listen_work+0x6ac/0xb80 net/smc/af_smc.c:935
3 locks held by kworker/0:6/12296:
 #0:  ("events"){+.+.}, at: [<ffffffff81364b80>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((&smc->tcp_listen_work)){+.+.}, at: [<ffffffff81364bb6>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_clcsock_accept net/smc/af_smc.c:600 [inline]
 #2:  (&smc->clcsock_release_lock){+.+.}, at: [<ffffffff86d4146c>] smc_tcp_listen_work+0x6ac/0xb80 net/smc/af_smc.c:935
1 lock held by syz-executor.2/13838:
 #0:  (net_mutex){+.+.}, at: [<ffffffff85c1d5f6>] copy_net_ns+0x156/0x440 net/core/net_namespace.c:411

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

NMI backtrace for cpu 0
CPU: 0 PID: 1533 Comm: khungtaskd Not tainted 4.14.258-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
CPU: 1 PID: 4623 Comm: systemd-journal Not tainted 4.14.258-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a1106100 task.stack: ffff8880a1108000
RIP: 0010:___bpf_prog_run+0xa5/0x5a70 kernel/bpf/core.c:961
RSP: 0018:ffff8880a110fa48 EFLAGS: 00000246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff8880a110fe68
RDX: 0000000000000000 RSI: ffffc90001a82030 RDI: ffffffff878f07c0
RBP: ffff8880a110fb58 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff878f0220
R13: 1ffff11014221f50 R14: ffffc90001a821f0 R15: 00000000000000b4
FS:  00007f7fb916c8c0(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7fb66c0028 CR3: 00000000a1707000 CR4: 00000000003426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
Code: f6 ff 4c 89 f0 4c 89 f2 48 c1 e8 03 83 e2 07 0f b6 04 18 38 d0 7f 08 84 c0 0f 85 10 42 00 00 45 0f b6 3e 4a 8d 3c fd 20 02 8f 87 <48> 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 ea 41 00 00 43 ff 24 fc 
----------------
Code disassembly (best guess):
   0:	f6 ff                	idiv   %bh
   2:	4c 89 f0             	mov    %r14,%rax
   5:	4c 89 f2             	mov    %r14,%rdx
   8:	48 c1 e8 03          	shr    $0x3,%rax
   c:	83 e2 07             	and    $0x7,%edx
   f:	0f b6 04 18          	movzbl (%rax,%rbx,1),%eax
  13:	38 d0                	cmp    %dl,%al
  15:	7f 08                	jg     0x1f
  17:	84 c0                	test   %al,%al
  19:	0f 85 10 42 00 00    	jne    0x422f
  1f:	45 0f b6 3e          	movzbl (%r14),%r15d
  23:	4a 8d 3c fd 20 02 8f 	lea    -0x7870fde0(,%r15,8),%rdi
  2a:	87
* 2b:	48 89 f8             	mov    %rdi,%rax <-- trapping instruction
  2e:	48 c1 e8 03          	shr    $0x3,%rax
  32:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1)
  36:	0f 85 ea 41 00 00    	jne    0x4226
  3c:	43 ff 24 fc          	jmpq   *(%r12,%r15,8)

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2021/12/20 05:05 linux-4.14.y 9dfbac0e6b86 44068e19 .config log report info INFO: task hung in tipc_exit_net
ci2-linux-4-14 2021/12/05 19:17 linux-4.14.y 66722c42ec91 a617004c .config log report info INFO: task hung in tipc_exit_net