INFO: task hung in xfrm_state_gc_task (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: ffa22221 ANDROID: cuttlefish_defconfig: Enable CONFIG_XFRM..
git tree: android-4.14
console output: https://syzkaller.appspot.com/x/log.txt?x=15de7b60a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=e770c80c00fb51d
dashboard link: https://syzkaller.appspot.com/bug?extid=dea941143edfb8bc7dcf
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+dea941...@syzkaller.appspotmail.com

INFO: task kworker/1:2:71 blocked for more than 140 seconds.
Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:2 D27800 71 2 0x80000000
Workqueue: events xfrm_state_gc_task
Call Trace:
schedule+0x92/0x1c0 kernel/sched/core.c:3498
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
__wait_rcu_gp+0x235/0x2f0 kernel/rcu/update.c:413
synchronize_rcu.part.0+0xc1/0xd0 kernel/rcu/tree_plugin.h:764
xfrm_state_gc_task+0xc0/0x550 net/xfrm/xfrm_state.c:467
process_one_work+0x7c6/0x1510 kernel/workqueue.c:2134
worker_thread+0x5d7/0x1080 kernel/workqueue.c:2271
kthread+0x310/0x420 kernel/kthread.c:232
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:402
INFO: task syz-executor.2:9781 blocked for more than 140 seconds.
Not tainted 4.14.113+ #61
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2 D28904 9781 1859 0x80000002
Call Trace:
schedule+0x92/0x1c0 kernel/sched/core.c:3498
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
__wait_rcu_gp+0x235/0x2f0 kernel/rcu/update.c:413
synchronize_rcu.part.0+0xc1/0xd0 kernel/rcu/tree_plugin.h:764
pfkey_release+0x231/0x2e0 net/key/af_key.c:193
__sock_release+0xd2/0x2c0 net/socket.c:602

Showing all locks held in the system:
1 lock held by khungtaskd/23:
#0: (tasklist_lock){.+.+}, at: [<000000002796c7c4>]
debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4544
2 locks held by kworker/1:2/71:
#0: ("events"){+.+.}, at: [<0000000071666e4d>]
process_one_work+0x6e5/0x1510 kernel/workqueue.c:2105
#1: (xfrm_state_gc_work){+.+.}, at: [<0000000064125ddf>]
process_one_work+0x71b/0x1510 kernel/workqueue.c:2109
2 locks held by getty/1761:
#0: (&tty->ldisc_sem){++++}, at: [<00000000fda48ffc>]
tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002ade0632>]
n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.2/4303:
#0: (rcu_preempt_state.barrier_mutex){+.+.}, at: [<00000000facdb433>]
_rcu_barrier+0x56/0x3e0 kernel/rcu/tree.c:3546
1 lock held by syz-executor.2/9781:
#0: (&sb->s_type->i_mutex_key#8){+.+.}, at: [<00000000d8345950>]
inode_lock include/linux/fs.h:715 [inline]
#0: (&sb->s_type->i_mutex_key#8){+.+.}, at: [<00000000d8345950>]
__sock_release+0x86/0x2c0 net/socket.c:601
1 lock held by syz-executor.0/9801:
#0: (rcu_preempt_state.barrier_mutex){+.+.}, at: [<00000000facdb433>]
_rcu_barrier+0x56/0x3e0 kernel/rcu/tree.c:3546

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

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.113+ #61
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9691 Comm: syz-executor.5 Not tainted 4.14.113+ #61
task: 000000006fc7152c task.stack: 00000000ac8ee7b5
RIP: 0033:0x40158b
RSP: 002b:00007fca08d09690 EFLAGS: 00000286
RAX: 00000000dbf26796 RBX: 000000000000000b RCX: 0000000000458da9
RDX: 0000000000000000 RSI: 00007fca08d096c0 RDI: 000000000000000b
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: ffffffff00000002 R14: 00000000305f6576 R15: 616c735f646e6f62
FS: 00007fca08d0a700(0000) GS:ffff8881dbb00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000dd2020 CR3: 00000001d4788001 CR4: 00000000001606a0


---
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[syzbot]

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