INFO: task hung in tun_chr_close (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11bed846080000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=6ba08f85642990d18341
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

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+6ba08f...@syzkaller.appspotmail.com

Bluetooth: hci8: command 0x041b tx timeout
Bluetooth: hci8: command 0x040f tx timeout
Bluetooth: hci8: command 0x0419 tx timeout
ieee802154 phy0 wpan0: encryption failed: -22
ieee802154 phy1 wpan1: encryption failed: -22
INFO: task syz-executor.4:1467 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D24120 1467 1 0x80000006
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619
__mutex_lock_common kernel/locking/mutex.c:1016 [inline]
__mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078
tun_detach drivers/net/tun.c:759 [inline]
tun_chr_close+0x3a/0x180 drivers/net/tun.c:3323
__fput+0x2ce/0x890 fs/file_table.c:278
task_work_run+0x148/0x1c0 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0xbf3/0x2be0 kernel/exit.c:870
do_group_exit+0x125/0x310 kernel/exit.c:967
get_signal+0x3f2/0x1f70 kernel/signal.c:2589
do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799
exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fc41f5fa6a7
Code: Bad RIP value.
RSP: 002b:00007fff790d6a30 EFLAGS: 00000293 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 0000000000000003 RCX: 00007fc41f5fa6a7
RDX: 0000000040000000 RSI: 00007fff790d6abc RDI: 00000000ffffffff
RBP: 00007fff790d6abc R08: 0000000000000000 R09: 00007fc41f6e3640
R10: 0000000000000000 R11: 0000000000000293 R12: 0000555557367810
R13: 000055555736786b R14: 000000000000001a R15: 00007fff790d6b20
INFO: task syz-executor.1:1810 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1 D28952 1810 32425 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619
__mutex_lock_common kernel/locking/mutex.c:1016 [inline]
__mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078
rtnl_lock net/core/rtnetlink.c:77 [inline]
rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:661
___sys_sendmsg+0x7bb/0x8e0 net/socket.c:2227
__sys_sendmsg net/socket.c:2265 [inline]
__do_sys_sendmsg net/socket.c:2274 [inline]
__se_sys_sendmsg net/socket.c:2272 [inline]
__x64_sys_sendmsg+0x132/0x220 net/socket.c:2272
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f5608668209
Code: Bad RIP value.
RSP: 002b:00007f5606fdd168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f560877af60 RCX: 00007f5608668209
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 00007f56086c2161 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff289ae29f R14: 00007f5606fdd300 R15: 0000000000022000
INFO: task syz-executor.4:1824 blocked for more than 140 seconds.
Not tainted 4.19.211-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D28648 1824 1 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2828 [inline]
__schedule+0x887/0x2040 kernel/sched/core.c:3517
schedule+0x8d/0x1b0 kernel/sched/core.c:3561
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619
__mutex_lock_common kernel/locking/mutex.c:1016 [inline]
__mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078
rtnl_lock net/core/rtnetlink.c:77 [inline]
rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
netlink_rcv_skb+0x160/0x440 net/netlink/af_netlink.c:2463
netlink_unicast_kernel net/netlink/af_netlink.c:1325 [inline]
netlink_unicast+0x4d5/0x690 net/netlink/af_netlink.c:1351
netlink_sendmsg+0x6c3/0xc50 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:661
__sys_sendto+0x21a/0x320 net/socket.c:1899
__do_sys_sendto net/socket.c:1911 [inline]
__se_sys_sendto net/socket.c:1907 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:1907
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fb42ecadfcc
Code: Bad RIP value.
RSP: 002b:00007ffca4834bf0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fb42fd46320 RCX: 00007fb42ecadfcc
RDX: 0000000000000028 RSI: 00007fb42fd46370 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffca4834c44 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fb42fd46370 R14: 0000000000000003 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/1570:
#0: 000000001555e70d (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
3 locks held by kworker/1:2/4692:
#0: 000000003ef944bd ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 00000000b70a2d1f ((linkwatch_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 0000000079b72d03 (rtnl_mutex){+.+.}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:236
1 lock held by in:imklog/7808:
#0: 0000000026ff8437 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by agetty/8029:
#0: 0000000004373d51 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 00000000e5854cab (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
3 locks held by kworker/1:4/9332:
#0: 000000003ef944bd ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 00000000ed1bc598 (deferred_process_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 0000000079b72d03 (rtnl_mutex){+.+.}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:150
3 locks held by syz-executor.2/13834:
3 locks held by kworker/0:6/30038:
#0: 000000001b3f2b05 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 0000000060148227 ((addr_chk_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 0000000079b72d03 (rtnl_mutex){+.+.}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4476
1 lock held by syz-executor.4/1307:
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: netdev_run_todo+0x719/0xab0 net/core/dev.c:9005
1 lock held by syz-executor.4/1467:
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: tun_detach drivers/net/tun.c:759 [inline]
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: tun_chr_close+0x3a/0x180 drivers/net/tun.c:3323
1 lock held by syz-executor.4/1756:
1 lock held by syz-executor.1/1810:
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.4/1824:
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.4/1838:
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
1 lock held by syz-executor.4/1853:
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 0000000079b72d03 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779

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

NMI backtrace for cpu 0
CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 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+0x991/0xe60 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: 13922 Comm: syz-executor.2 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
RIP: 0010:do_syscall_64+0x37e/0x620 arch/x86/entry/common.c:297
Code: fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e d4 01 00 00 83 63 08 f9 0f 1f 44 00 00 e8 d9 0b 62 00 0f 00 2d 02 e4 5f 07 <48> 83 c4 08 5b 5d 41 5c 41 5d e9 c3 0b 62 00 e8 be 0b 62 00 48 b8
RSP: 0018:ffff88804d36ff28 EFLAGS: 000000d3
RAX: ffff888095f4a600 RBX: ffff888095f4a600 RCX: ffffffff81007956
RDX: 0000000000000000 RSI: ffffffff81007997 RDI: ffff888095f4a608
RBP: ffff88804d36ff58 R08: ffff88804d36fab8 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00000000200026c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb42ecadfa2 CR3: 00000000a85a3000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f800433276f
Code: 89 d8 83 e0 0c 83 f8 04 74 01 c3 64 48 8b 3c 25 00 00 00 00 b8 ca 00 00 00 4d 31 d2 48 81 c7 08 03 00 00 be 80 00 00 00 0f 05 <64> 8b 04 25 08 03 00 00 eb ce 0f 1f 80 00 00 00 00 4c 8b 0f 48 89
RSP: 002b:00007f8002c630a8 EFLAGS: 00000286 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffea RBX: 00007f8004422030 RCX: 00007f800433276f
RDX: 00007f8002c630f0 RSI: 0000000000000080 RDI: 90e0524d0055832e
RBP: 00007f8004369161 R08: 000000000880ec95 R09: 00000000200026c0
R10: 0000000000000000 R11: 0000000000000286 R12: 0000000000000000
R13: 00007ffe00da14ff R14: 00007f8002c63300 R15: 0000000000022000


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[syzbot]

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