INFO: task hung in addrconf_dad

[upstream] INFO: task hung in addrconf_dad_work
Status: moderation: reported on 2018/03/30 20:01
Reported-by: syzbot+63fcb43f66d666cf0974@syzkaller.appspotmail.com
First: 177d, last: 177d

Sample crash report:

IPVS: ftp: loaded support on port[0] = 21
kernel msg: ebtables bug: please report to author: Wrong len argument
IPVS: ftp: loaded support on port[0] = 21
kernel msg: ebtables bug: please report to author: Wrong len argument
INFO: task kworker/1:3:2041 blocked for more than 120 seconds.
      Not tainted 4.16.0-rc6+ #286
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:3     D21232  2041      2 0x80000000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
 context_switch kernel/sched/core.c:2862 [inline]
 __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440
 schedule+0xf5/0x430 kernel/sched/core.c:3499
 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3557
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
 rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74
 addrconf_dad_work+0xc0/0x1320 net/ipv6/addrconf.c:3946
 process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113
 worker_thread+0x223/0x1990 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
INFO: lockdep is turned off.
NMI backtrace for cpu 1
CPU: 1 PID: 871 Comm: khungtaskd Not tainted 4.16.0-rc6+ #286
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+0x194/0x24d lib/dump_stack.c:53
 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x90c/0xd60 kernel/hung_task.c:249
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
Kernel panic - not syncing: hung_task: blocked tasks
CPU: 1 PID: 871 Comm: khungtaskd Not tainted 4.16.0-rc6+ #286
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+0x194/0x24d lib/dump_stack.c:53
 panic+0x1e4/0x41c kernel/panic.c:183
 check_hung_task kernel/hung_task.c:133 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x91d/0xd60 kernel/hung_task.c:249
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

All crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	Maintainers
ci-upstream-net-kasan-gce	2018/03/30 16:13	net-next	18845557	d47f0ed6	.config	log	report			christian.brauner@ubuntu.com, davem@davemloft.net, dsahern@gmail.com, fw@strlen.de, jbenc@redhat.com, ktkhai@virtuozzo.com, linux-kernel@vger.kernel.org, lucien.xin@gmail.com, netdev@vger.kernel.org, vyasevich@gmail.com