INFO: task hung in raw_close

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: b11964ad ANDROID: cuttlefish: enable CONFIG_INET_UDP_DIAG=y
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=1787df57200000
kernel config: https://syzkaller.appspot.com/x/.config?x=322dd7397c84f390
dashboard link: https://syzkaller.appspot.com/bug?extid=14e7fe761e2d6bda3c5e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+14e7fe...@syzkaller.appspotmail.com

ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
ip6_tunnel: ip6tnl1 xmit: Local address not yet configured!
INFO: task syz-executor.4:21278 blocked for more than 140 seconds.
Not tainted 4.14.105+ #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D27984 21278 1850 0x80000002
Call Trace:
schedule+0x92/0x1c0 kernel/sched/core.c:3492
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3550
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x559/0x1430 kernel/locking/mutex.c:893
raw_close+0xe/0x30 net/ipv4/raw.c:699
inet_release+0xe9/0x1c0 net/ipv4/af_inet.c:440
__sock_release+0xd2/0x250 net/socket.c:602
INFO: task kworker/u4:32:7146 blocked for more than 140 seconds.
Not tainted 4.14.105+ #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:32 D26456 7146 2 0x80000000
Workqueue: netns cleanup_net
Call Trace:
schedule+0x92/0x1c0 kernel/sched/core.c:3492
schedule_timeout+0x736/0xe80 kernel/time/timer.c:1721
do_wait_for_common kernel/sched/completion.c:91 [inline]
__wait_for_common kernel/sched/completion.c:112 [inline]
wait_for_common+0x29c/0x470 kernel/sched/completion.c:123
flush_work+0x3d2/0x710 kernel/workqueue.c:2885
flush_all_backlogs net/core/dev.c:4660 [inline]
rollback_registered_many+0x4f0/0xab0 net/core/dev.c:7196
INFO: task syz-executor.4:22462 blocked for more than 140 seconds.
Not tainted 4.14.105+ #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4 D26680 22462 1850 0x00000004
Call Trace:
schedule+0x92/0x1c0 kernel/sched/core.c:3492
schedule_timeout+0x736/0xe80 kernel/time/timer.c:1721
do_wait_for_common kernel/sched/completion.c:91 [inline]
__wait_for_common kernel/sched/completion.c:112 [inline]
wait_for_common+0x29c/0x470 kernel/sched/completion.c:123
flush_work+0x3d2/0x710 kernel/workqueue.c:2885
lru_add_drain_all_cpuslocked mm/swap.c:722 [inline]
lru_add_drain_all_cpuslocked+0x2d5/0x420 mm/swap.c:691
lru_add_drain_all+0xf/0x20 mm/swap.c:730
do_mlock+0x90/0x5d0 mm/mlock.c:673
SYSC_mlock2 mm/mlock.c:726 [inline]
SyS_mlock2+0x49/0x70 mm/mlock.c:716
do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289

Showing all locks held in the system:
1 lock held by khungtaskd/23:
#0: (tasklist_lock){.+.?}, at: [<ffffffff87600e0c>]
debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1754:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff88138782>]
tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:275
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff88133ba7>]
n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
2 locks held by syz-executor.4/21278:
#0: (&sb->s_type->i_mutex_key#8){+.+.}, at: [<ffffffff8869dd26>]
inode_lock include/linux/fs.h:715 [inline]
#0: (&sb->s_type->i_mutex_key#8){+.+.}, at: [<ffffffff8869dd26>]
__sock_release+0x86/0x250 net/socket.c:601
#1: (rtnl_mutex){+.+.}, at: [<ffffffff88955d5e>] raw_close+0xe/0x30
net/ipv4/raw.c:699
5 locks held by kworker/u4:32/7146:
#0: ("%s""netns"){+.+.}, at: [<ffffffff875287d5>]
process_one_work+0x6e5/0x14e0 kernel/workqueue.c:2085
#1: (net_cleanup_work){+.+.}, at: [<ffffffff8752880b>]
process_one_work+0x71b/0x14e0 kernel/workqueue.c:2089
#2: (net_mutex){+.+.}, at: [<ffffffff886eefd6>] cleanup_net+0x136/0x860
net/core/net_namespace.c:449
#3: (rtnl_mutex){+.+.}, at: [<ffffffff88baf421>]
ip6_tnl_exit_net+0x71/0x550 net/ipv6/ip6_tunnel.c:2265
#4: (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff88709aaa>]
get_online_cpus include/linux/cpu.h:138 [inline]
#4: (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff88709aaa>]
flush_all_backlogs net/core/dev.c:4653 [inline]
#4: (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff88709aaa>]
rollback_registered_many+0x40a/0xab0 net/core/dev.c:7196
2 locks held by syz-executor.4/22462:
#0: (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff8785d0ba>]
get_online_cpus include/linux/cpu.h:138 [inline]
#0: (cpu_hotplug_lock.rw_sem){++++}, at: [<ffffffff8785d0ba>]
lru_add_drain_all+0xa/0x20 mm/swap.c:729
#1: (lock#4){+.+.}, at: [<ffffffff8785ccfc>]
lru_add_drain_all_cpuslocked+0x6c/0x420 mm/swap.c:704

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

NMI backtrace for cpu 1
CPU: 1 PID: 23 Comm: khungtaskd Not tainted 4.14.105+ #29
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0xb9/0x10e lib/dump_stack.c:53
nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 22441 Comm: syz-executor.3 Not tainted 4.14.105+ #29
task: ffff8881d291af00 task.stack: ffff8881aae08000
RIP: 0033:0x401594
RSP: 002b:00007fc16b854690 EFLAGS: 00000202
RAX: 0000000021bd06dc RBX: 000000000000000b RCX: 0000000000457f29
RDX: 0000000000000000 RSI: 00007fc16b8546c0 RDI: 000000000000000b
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 00007fc16b855700(0000) GS:ffff8881dba00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000073c000 CR3: 000000015a4b2006 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600


---
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[syzbot]

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