INFO: task hung in reg_check_chans_work

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syzbot

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Feb 14, 2018, 8:59:05ā€ÆAM2/14/18
to christia...@ubuntu.com, dan...@iogearbox.net, da...@davemloft.net, dsa...@gmail.com, f...@strlen.de, jakub.k...@netronome.com, jb...@redhat.com, linux-...@vger.kernel.org, lucie...@gmail.com, msch...@universe-factory.net, net...@vger.kernel.org, syzkall...@googlegroups.com, vyas...@gmail.com
Hello,

syzbot hit the following crash on upstream commit
cbd7b8a76b79a2ff6112ef2e77031b694843b8a1 (Tue Feb 6 23:30:52 2018 +0000)
Merge tag 'platform-drivers-x86-v4.16-1' of
git://git.infradead.org/linux-platform-drivers-x86

So far this crash happened 6 times on net-next, upstream.
Unfortunately, I don't have any reproducer for this crash yet.
Raw console output is attached.
compiler: gcc (GCC) 7.1.1 20170620
.config is attached.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c57335...@syzkaller.appspotmail.com
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Cannot find add_set index 2048 as target
INFO: task kworker/1:3:5678 blocked for more than 120 seconds.
Not tainted 4.15.0+ #300
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:3 D22704 5678 2 0x80000000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
context_switch kernel/sched/core.c:2845 [inline]
__schedule+0x8eb/0x2060 kernel/sched/core.c:3421
schedule+0xf5/0x430 kernel/sched/core.c:3480
schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3538
__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
reg_check_chans_work+0xaa/0xff0 net/wireless/reg.c:2017
process_one_work+0xbbf/0x1af0 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:429

Showing all locks held in the system:
2 locks held by khungtaskd/759:
#0: (rcu_read_lock){....}, at: [<00000000d4470309>]
check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
#0: (rcu_read_lock){....}, at: [<00000000d4470309>] watchdog+0x1c5/0xd60
kernel/hung_task.c:249
#1: (tasklist_lock){.+.+}, at: [<0000000037ffdeeb>]
debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470
3 locks held by kworker/0:3/1827:
#0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at:
[<000000008982763e>] process_one_work+0xaaf/0x1af0 kernel/workqueue.c:2084
#1: ((addr_chk_work).work){+.+.}, at: [<00000000274eb49e>]
process_one_work+0xb01/0x1af0 kernel/workqueue.c:2088
#2: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by rsyslogd/4013:
#0: (&f->f_pos_lock){+.+.}, at: [<0000000008f3ba06>]
__fdget_pos+0x12b/0x190 fs/file.c:765
2 locks held by getty/4134:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/4135:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/4136:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/4137:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/4138:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/4139:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/4140:
#0: (&tty->ldisc_sem){++++}, at: [<00000000d8e84bec>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003438beb0>]
n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
3 locks held by kworker/1:3/5678:
#0: ((wq_completion)"events_power_efficient"){+.+.}, at:
[<000000008982763e>] process_one_work+0xaaf/0x1af0 kernel/workqueue.c:2084
#1: ((reg_check_chans).work){+.+.}, at: [<00000000274eb49e>]
process_one_work+0xb01/0x1af0 kernel/workqueue.c:2088
#2: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by syz-executor2/11029:
#0: (sk_lock-AF_INET6){+.+.}, at: [<0000000050f92c05>] lock_sock
include/net/sock.h:1463 [inline]
#0: (sk_lock-AF_INET6){+.+.}, at: [<0000000050f92c05>]
ipv6_getsockopt+0x1c5/0x2e0 net/ipv6/ipv6_sockglue.c:1370
1 lock held by syz-executor2/11040:
#0: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by syz-executor2/11047:
#0: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by syz-executor2/11051:
#0: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by syz-executor2/11054:
#0: (sk_lock-AF_INET6){+.+.}, at: [<0000000050f92c05>] lock_sock
include/net/sock.h:1463 [inline]
#0: (sk_lock-AF_INET6){+.+.}, at: [<0000000050f92c05>]
ipv6_getsockopt+0x1c5/0x2e0 net/ipv6/ipv6_sockglue.c:1370
1 lock held by syz-executor2/11055:
#0: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by syz-executor2/11056:
#0: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74
1 lock held by syz-executor2/11057:
#0: (rtnl_mutex){+.+.}, at: [<00000000b75e700b>] rtnl_lock+0x17/0x20
net/core/rtnetlink.c:74

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

NMI backtrace for cpu 0
CPU: 0 PID: 759 Comm: khungtaskd Not tainted 4.15.0+ #300
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+0x194/0x257 lib/dump_stack.c:53
nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x122/0x180 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:429
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10
arch/x86/include/asm/irqflags.h:54


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This bug is generated by a dumb bot. It may contain errors.
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Dmitry Vyukov

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Feb 14, 2018, 10:30:36ā€ÆAM2/14/18
to syzbot, Christian Brauner, Daniel Borkmann, David Miller, David Ahern, Florian Westphal, Jakub Kicinski, Jiri Benc, LKML, Xin Long, msch...@universe-factory.net, netdev, syzkall...@googlegroups.com, Vladislav Yasevich
On Wed, Feb 14, 2018 at 2:59 PM, syzbot
<syzbot+c57335...@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot hit the following crash on upstream commit
> cbd7b8a76b79a2ff6112ef2e77031b694843b8a1 (Tue Feb 6 23:30:52 2018 +0000)
> Merge tag 'platform-drivers-x86-v4.16-1' of
> git://git.infradead.org/linux-platform-drivers-x86
>
> So far this crash happened 6 times on net-next, upstream.
> Unfortunately, I don't have any reproducer for this crash yet.
> Raw console output is attached.
> compiler: gcc (GCC) 7.1.1 20170620
> .config is attached.

Another hang on rtnl lock:

#syz dup: INFO: task hung in linkwatch_event
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Dmitry Vyukov

unread,
Feb 14, 2018, 10:33:09ā€ÆAM2/14/18
to syzbot, syzkall...@googlegroups.com
On Wed, Feb 14, 2018 at 4:30 PM, Dmitry Vyukov <dvy...@google.com> wrote:
> On Wed, Feb 14, 2018 at 2:59 PM, syzbot
> <syzbot+c57335...@syzkaller.appspotmail.com> wrote:
>> Hello,
>>
>> syzbot hit the following crash on upstream commit
>> cbd7b8a76b79a2ff6112ef2e77031b694843b8a1 (Tue Feb 6 23:30:52 2018 +0000)
>> Merge tag 'platform-drivers-x86-v4.16-1' of
>> git://git.infradead.org/linux-platform-drivers-x86
>>
>> So far this crash happened 6 times on net-next, upstream.
>> Unfortunately, I don't have any reproducer for this crash yet.
>> Raw console output is attached.
>> compiler: gcc (GCC) 7.1.1 20170620
>> .config is attached.
>
> Another hang on rtnl lock:
>
> #syz dup: INFO: task hung in linkwatch_event


There are already some deadlocks duped onto this one:

#syz dup: INFO: task hung in netdev_run_todo
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