INFO: task hung in cfg80211_dfs_channels_update_work (2)

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syzbot

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Jan 15, 2022, 2:22:17 AM1/15/22
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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=137ce87bb00000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=ae073377a78d5623bdca
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+ae0733...@syzkaller.appspotmail.com

batman_adv: batadv0: Interface deactivated: gretap650
batman_adv: batadv0: Interface deactivated: gretap651
batman_adv: batadv0: Interface deactivated: gretap652
batman_adv: batadv0: Interface deactivated: gretap653
batman_adv: batadv0: Interface deactivated: gretap654
INFO: task kworker/u4:7:20463 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.
kworker/u4:7 D25536 20463 2 0x80000000
Workqueue: cfg80211 cfg80211_dfs_channels_update_work
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
cfg80211_dfs_channels_update_work+0x98/0x5a0 net/wireless/mlme.c:777
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
INFO: task kworker/1:0:9636 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.
kworker/1:0 D27016 9636 2 0x80000000
Workqueue: events switchdev_deferred_process_work
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
switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:150
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
batman_adv: batadv0: Interface deactivated: gretap655
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
INFO: task kworker/1:3:23492 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.
kworker/1:3 D27032 23492 2 0x80000000
Workqueue: events linkwatch_event
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
linkwatch_event+0xb/0x60 net/core/link_watch.c:236
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Showing all locks held in the system:
1 lock held by khungtaskd/1571:
#0: 000000001914357c (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441
4 locks held by kworker/u4:5/6805:
1 lock held by in:imklog/7770:
#0: 00000000905a5570 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
batman_adv: batadv0: Interface deactivated: gretap656
2 locks held by agetty/7818:
#0: 0000000085a0db02 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
#1: 000000000a0975b1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
3 locks held by kworker/u4:7/20463:
#0: 00000000b501892a ((wq_completion)"cfg80211"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 000000001b9b4cac ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 000000002d4b4702 (rtnl_mutex){+.+.}, at: cfg80211_dfs_channels_update_work+0x98/0x5a0 net/wireless/mlme.c:777
3 locks held by kworker/1:0/9636:
#0: 000000005d93094d ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 000000000b0eeaae (deferred_process_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 000000002d4b4702 (rtnl_mutex){+.+.}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:150
3 locks held by kworker/1:3/23492:
#0: 000000005d93094d ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 00000000a029bb0a ((linkwatch_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 000000002d4b4702 (rtnl_mutex){+.+.}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:236
2 locks held by syz-executor.0/19223:
#0: 000000002d4b4702 (rtnl_mutex){+.+.}, at: rtnl_lock net/core/rtnetlink.c:77 [inline]
#0: 000000002d4b4702 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x3fe/0xb80 net/core/rtnetlink.c:4779
#1: 000000008cde8d47 (rcu_preempt_state.exp_mutex){+.+.}, at: exp_funnel_lock kernel/rcu/tree_exp.h:297 [inline]
#1: 000000008cde8d47 (rcu_preempt_state.exp_mutex){+.+.}, at: _synchronize_rcu_expedited+0x4dc/0x6f0 kernel/rcu/tree_exp.h:667
2 locks held by kworker/1:1/19338:
#0: 0000000080891f2d ((wq_completion)"rcu_gp"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 000000004cf9e96c ((work_completion)(&rew.rew_work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
3 locks held by kworker/1:4/19339:
#0: 00000000c7668a5f ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124
#1: 0000000088b96b7b ((addr_chk_work).work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128
#2: 000000002d4b4702 (rtnl_mutex){+.+.}, at: addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4476

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

NMI backtrace for cpu 1
CPU: 1 PID: 1571 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6805 Comm: kworker/u4:5 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet
RIP: 0010:__lock_acquire+0x25d/0x3ff0 kernel/locking/lockdep.c:3322
Code: 85 c0 0f 84 38 ff ff ff 48 8d b8 38 01 00 00 be 04 00 00 00 48 89 44 24 10 e8 bf 54 4d 00 48 8b 44 24 10 f0 ff 80 38 01 00 00 <49> 8d b5 80 08 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 f1 48 89
RSP: 0018:ffff88809f4a7978 EFLAGS: 00000006
RAX: ffffffff8cd63090 RBX: 0000000000000000 RCX: ffffffff814afa31
RDX: fffffbfff19ac63a RSI: 0000000000000004 RDI: ffffffff8cd631c8
RBP: 0000000000000002 R08: 0000000000000001 R09: fffffbfff19ac639
R10: ffffffff8cd631cb R11: 0000000000000000 R12: 0000000000000000
R13: ffff88809f12c400 R14: ffffffff89f85fa0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ba000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc2bf8e4000 CR3: 0000000024713000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
rcu_lock_acquire include/linux/rcupdate.h:242 [inline]
rcu_read_lock include/linux/rcupdate.h:627 [inline]
batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:942 [inline]
batadv_iv_ogm_schedule_buff+0x5bb/0x1340 net/batman-adv/bat_iv_ogm.c:1008
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:1052 [inline]
batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:1045 [inline]
batadv_iv_send_outstanding_bat_ogm_packet+0x68c/0x7a0 net/batman-adv/bat_iv_ogm.c:1871
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
----------------
Code disassembly (best guess):
0: 85 c0 test %eax,%eax
2: 0f 84 38 ff ff ff je 0xffffff40
8: 48 8d b8 38 01 00 00 lea 0x138(%rax),%rdi
f: be 04 00 00 00 mov $0x4,%esi
14: 48 89 44 24 10 mov %rax,0x10(%rsp)
19: e8 bf 54 4d 00 callq 0x4d54dd
1e: 48 8b 44 24 10 mov 0x10(%rsp),%rax
23: f0 ff 80 38 01 00 00 lock incl 0x138(%rax)
* 2a: 49 8d b5 80 08 00 00 lea 0x880(%r13),%rsi <-- trapping instruction
31: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
38: fc ff df
3b: 48 89 f1 mov %rsi,%rcx
3e: 48 rex.W
3f: 89 .byte 0x89


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syzbot

unread,
May 15, 2022, 3:22:16 AM5/15/22
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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