[syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)

[syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    2a130b7e1fcd Merge tag 'kbuild-fixes-v6.12' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1206e79f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f38c36a955431c1
dashboard link: https://syzkaller.appspot.com/bug?extid=5506b2556159a1ab6923
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=155b8327980000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-2a130b7e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ea0b899b6053/vmlinux-2a130b7e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4ef0bad329fe/bzImage-2a130b7e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5506b2556159a1ab6923@syzkaller.appspotmail.com

INFO: task kworker/u4:4:5271 blocked for more than 143 seconds.
      Not tainted 6.12.0-rc1-syzkaller-00381-g2a130b7e1fcd #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:4    state:D stack:25712 pid:5271  tgid:5271  ppid:2      flags:0x00004000
Workqueue: cfg80211 cfg80211_event_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1895/0x4b30 kernel/sched/core.c:6675
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 wiphy_lock include/net/cfg80211.h:6014 [inline]
 cfg80211_event_work+0x27/0x40 net/wireless/core.c:334
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/25:
 #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
1 lock held by kswapd0/73:
3 locks held by kworker/0:3/909:
3 locks held by kworker/u4:9/2509:
3 locks held by kworker/u4:11/3318:
1 lock held by dhcpcd/4814:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
2 locks held by getty/4897:
 #0: ffff88801dda90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
3 locks held by kworker/u4:0/5118:
 #0: ffff88803c425948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88803c425948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90002d1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002d1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4196
3 locks held by kworker/0:2/5170:
2 locks held by kworker/u4:2/5176:
3 locks held by kworker/u4:3/5211:
1 lock held by syz-executor/5254:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
1 lock held by syz-executor/5255:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
1 lock held by syz-executor/5258:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
1 lock held by syz-executor/5264:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
3 locks held by kworker/u4:4/5271:
 #0: ffff88801ebdf948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ebdf948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90002617d00 ((work_completion)(&rdev->event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002617d00 ((work_completion)(&rdev->event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
 #2: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_event_work+0x27/0x40 net/wireless/core.c:334
1 lock held by syz-executor/5273:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
3 locks held by kworker/u4:6/5278:
4 locks held by kworker/0:6/5390:
 #0: ffff88801ac75948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac75948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90002adfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002adfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x99/0xfd0 net/wireless/reg.c:2480
 #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
 #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: reg_leave_invalid_chans net/wireless/reg.c:2468 [inline]
 #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: reg_check_chans_work+0x164/0xfd0 net/wireless/reg.c:2483
3 locks held by kworker/0:9/5444:
3 locks held by kworker/0:10/5446:
2 locks held by kworker/0:12/5449:
3 locks held by kworker/0:14/5454:
2 locks held by kworker/0:15/5455:
3 locks held by kworker/0:16/5456:
4 locks held by kworker/u4:10/5469:
 #0: ffff88801be8b148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801be8b148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90002cafd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90002cafd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcc51d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
 #3: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1f/0x1e0 drivers/net/wireguard/device.c:414
2 locks held by kworker/u4:13/5492:
1 lock held by syz-executor/5502:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5515:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5522:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5526:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5534:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5535:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5550:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5553:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5557:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5562:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5569:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
1 lock held by syz-executor/5573:
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
 #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25 Comm: khungtaskd Not tainted 6.12.0-rc1-syzkaller-00381-g2a130b7e1fcd #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)

[Ben Greear]

On 10/10/24 08:19, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    2a130b7e1fcd Merge tag 'kbuild-fixes-v6.12' of git://git.k..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1206e79f980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f38c36a955431c1
> dashboard link: https://syzkaller.appspot.com/bug?extid=5506b2556159a1ab6923
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=155b8327980000

This looks like something I saw in 6.11 and 6.10.  My guess was that one of the
running processes that lockdep does not print locks for is holding the wiphy mtx.

Maybe it would help if syzbot would use sysrq to dump all running tasks to the console, and maybe
lockdep could print locks for running processes, even if they are marked as potentially
unreliable?

Thanks,
Ben

> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-2a130b7e.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/ea0b899b6053/vmlinux-2a130b7e.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/4ef0bad329fe/bzImage-2a130b7e.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+5506b2556159a1ab6923@syzkaller.appspotmail.com
> 
> INFO: task kworker/u4:4:5271 blocked for more than 143 seconds.
>        Not tainted 6.12.0-rc1-syzkaller-00381-g2a130b7e1fcd #0
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> task:kworker/u4:4    state:D stack:25712 pid:5271  tgid:5271  ppid:2      flags:0x00004000
> Workqueue: cfg80211 cfg80211_event_work
> Call Trace:
>   <TASK>
>   context_switch kernel/sched/core.c:5315 [inline]
>   __schedule+0x1895/0x4b30 kernel/sched/core.c:6675
>   __schedule_loop kernel/sched/core.c:6752 [inline]
>   schedule+0x14b/0x320 kernel/sched/core.c:6767
>   schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
>   __mutex_lock_common kernel/locking/mutex.c:684 [inline]
>   __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
>   wiphy_lock include/net/cfg80211.h:6014 [inline]
>   cfg80211_event_work+0x27/0x40 net/wireless/core.c:334
>   process_one_work kernel/workqueue.c:3229 [inline]
>   process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
>   worker_thread+0x870/0xd30 kernel/workqueue.c:3391
>   kthread+0x2f0/0x390 kernel/kthread.c:389
>   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>   </TASK>
> 
> Showing all locks held in the system:
> 1 lock held by khungtaskd/25:
>   #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
>   #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
>   #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
> 1 lock held by kswapd0/73:
> 3 locks held by kworker/0:3/909:
> 3 locks held by kworker/u4:9/2509:
> 3 locks held by kworker/u4:11/3318:
> 1 lock held by dhcpcd/4814:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 2 locks held by getty/4897:
>   #0: ffff88801dda90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
>   #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
> 3 locks held by kworker/u4:0/5118:
>   #0: ffff88803c425948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
>   #0: ffff88803c425948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
>   #1: ffffc90002d1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
>   #1: ffffc90002d1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
>   #2: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4196
> 3 locks held by kworker/0:2/5170:
> 2 locks held by kworker/u4:2/5176:
> 3 locks held by kworker/u4:3/5211:
> 1 lock held by syz-executor/5254:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> 1 lock held by syz-executor/5255:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> 1 lock held by syz-executor/5258:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> 1 lock held by syz-executor/5264:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> 3 locks held by kworker/u4:4/5271:
>   #0: ffff88801ebdf948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
>   #0: ffff88801ebdf948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
>   #1: ffffc90002617d00 ((work_completion)(&rdev->event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
>   #1: ffffc90002617d00 ((work_completion)(&rdev->event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
>   #2: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
>   #2: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_event_work+0x27/0x40 net/wireless/core.c:334
> 1 lock held by syz-executor/5273:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> 3 locks held by kworker/u4:6/5278:
> 4 locks held by kworker/0:6/5390:
>   #0: ffff88801ac75948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
>   #0: ffff88801ac75948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
>   #1: ffffc90002adfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
>   #1: ffffc90002adfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
>   #2: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x99/0xfd0 net/wireless/reg.c:2480
>   #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
>   #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: reg_leave_invalid_chans net/wireless/reg.c:2468 [inline]
>   #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: reg_check_chans_work+0x164/0xfd0 net/wireless/reg.c:2483
> 3 locks held by kworker/0:9/5444:
> 3 locks held by kworker/0:10/5446:
> 2 locks held by kworker/0:12/5449:
> 3 locks held by kworker/0:14/5454:
> 2 locks held by kworker/0:15/5455:
> 3 locks held by kworker/0:16/5456:
> 4 locks held by kworker/u4:10/5469:
>   #0: ffff88801be8b148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
>   #0: ffff88801be8b148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
>   #1: ffffc90002cafd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
>   #1: ffffc90002cafd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
>   #2: ffffffff8fcc51d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
>   #3: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1f/0x1e0 drivers/net/wireguard/device.c:414
> 2 locks held by kworker/u4:13/5492:
> 1 lock held by syz-executor/5502:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5515:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5522:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5526:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5534:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5535:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5550:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5553:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5557:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5562:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5569:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 1 lock held by syz-executor/5573:
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
>   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> 
> =============================================


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: [syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)

[Aleksandr Nogikh]

Hi Ben,

On Fri, Oct 11, 2024 at 11:50 AM Ben Greear <greearb@candelatech.com> wrote:
>
> On 10/10/24 08:19, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    2a130b7e1fcd Merge tag 'kbuild-fixes-v6.12' of git://git.k..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1206e79f980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=f38c36a955431c1
> > dashboard link: https://syzkaller.appspot.com/bug?extid=5506b2556159a1ab6923
> > compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=155b8327980000
>
> This looks like something I saw in 6.11 and 6.10.  My guess was that one of the
> running processes that lockdep does not print locks for is holding the wiphy mtx.
>
> Maybe it would help if syzbot would use sysrq to dump all running tasks to the console, and maybe
> lockdep could print locks for running processes, even if they are marked as potentially
> unreliable?

Thanks for the suggestions!

We do have an open issue re. SysRq:
https://github.com/google/syzkaller/issues/4200
I've noted a +1 to that.

Regarding the locks -- they are actually already printed in the
original bug report, under "Showing all locks held in the system:". Or
did you mean something else?

-- 
Aleksandr

>
> Thanks,
> Ben
>
> >
> > Downloadable assets:
> > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-2a130b7e.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/ea0b899b6053/vmlinux-2a130b7e.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/4ef0bad329fe/bzImage-2a130b7e.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+5506b2556159a1ab6923@syzkaller.appspotmail.com
> >
> > INFO: task kworker/u4:4:5271 blocked for more than 143 seconds.
> >        Not tainted 6.12.0-rc1-syzkaller-00381-g2a130b7e1fcd #0
> > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> > task:kworker/u4:4    state:D stack:25712 pid:5271  tgid:5271  ppid:2      flags:0x00004000
> > Workqueue: cfg80211 cfg80211_event_work
> > Call Trace:
> >   <TASK>
> >   context_switch kernel/sched/core.c:5315 [inline]
> >   __schedule+0x1895/0x4b30 kernel/sched/core.c:6675
> >   __schedule_loop kernel/sched/core.c:6752 [inline]
> >   schedule+0x14b/0x320 kernel/sched/core.c:6767
> >   schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
> >   __mutex_lock_common kernel/locking/mutex.c:684 [inline]
> >   __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
> >   wiphy_lock include/net/cfg80211.h:6014 [inline]
> >   cfg80211_event_work+0x27/0x40 net/wireless/core.c:334
> >   process_one_work kernel/workqueue.c:3229 [inline]
> >   process_scheduled_works+0xa63/0x1850 kernel/workqueue.c:3310
> >   worker_thread+0x870/0xd30 kernel/workqueue.c:3391
> >   kthread+0x2f0/0x390 kernel/kthread.c:389
> >   ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
> >   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> >   </TASK>
> >
> > Showing all locks held in the system:
> > 1 lock held by khungtaskd/25:
> >   #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
> >   #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
> >   #0: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6720
> > 1 lock held by kswapd0/73:
> > 3 locks held by kworker/0:3/909:
> > 3 locks held by kworker/u4:9/2509:
> > 3 locks held by kworker/u4:11/3318:
> > 1 lock held by dhcpcd/4814:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 2 locks held by getty/4897:
> >   #0: ffff88801dda90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
> >   #1: ffffc9000039b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
> > 3 locks held by kworker/u4:0/5118:
> >   #0: ffff88803c425948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
> >   #0: ffff88803c425948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
> >   #1: ffffc90002d1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
> >   #1: ffffc90002d1fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
> >   #2: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4196
> > 3 locks held by kworker/0:2/5170:
> > 2 locks held by kworker/u4:2/5176:
> > 3 locks held by kworker/u4:3/5211:
> > 1 lock held by syz-executor/5254:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> > 1 lock held by syz-executor/5255:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> > 1 lock held by syz-executor/5258:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> > 1 lock held by syz-executor/5264:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> > 3 locks held by kworker/u4:4/5271:
> >   #0: ffff88801ebdf948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
> >   #0: ffff88801ebdf948 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
> >   #1: ffffc90002617d00 ((work_completion)(&rdev->event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
> >   #1: ffffc90002617d00 ((work_completion)(&rdev->event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
> >   #2: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
> >   #2: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_event_work+0x27/0x40 net/wireless/core.c:334
> > 1 lock held by syz-executor/5273:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_detach drivers/net/tun.c:698 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: tun_chr_close+0x3b/0x1b0 drivers/net/tun.c:3517
> > 3 locks held by kworker/u4:6/5278:
> > 4 locks held by kworker/0:6/5390:
> >   #0: ffff88801ac75948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
> >   #0: ffff88801ac75948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
> >   #1: ffffc90002adfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
> >   #1: ffffc90002adfd00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
> >   #2: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x99/0xfd0 net/wireless/reg.c:2480
> >   #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:6014 [inline]
> >   #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: reg_leave_invalid_chans net/wireless/reg.c:2468 [inline]
> >   #3: ffff888055538768 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: reg_check_chans_work+0x164/0xfd0 net/wireless/reg.c:2483
> > 3 locks held by kworker/0:9/5444:
> > 3 locks held by kworker/0:10/5446:
> > 2 locks held by kworker/0:12/5449:
> > 3 locks held by kworker/0:14/5454:
> > 2 locks held by kworker/0:15/5455:
> > 3 locks held by kworker/0:16/5456:
> > 4 locks held by kworker/u4:10/5469:
> >   #0: ffff88801be8b148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
> >   #0: ffff88801be8b148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
> >   #1: ffffc90002cafd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
> >   #1: ffffc90002cafd00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
> >   #2: ffffffff8fcc51d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
> >   #3: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1f/0x1e0 drivers/net/wireguard/device.c:414
> > 2 locks held by kworker/u4:13/5492:
> > 1 lock held by syz-executor/5502:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5515:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5522:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5526:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5534:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5535:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5550:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5553:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5557:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5562:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5569:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> > 1 lock held by syz-executor/5573:
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:79 [inline]
> >   #0: ffffffff8fcd1cc8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x6e6/0xcf0 net/core/rtnetlink.c:6643
> >
> > =============================================
>
>
> --
> Ben Greear <greearb@candelatech.com>
> Candela Technologies Inc  http://www.candelatech.com
>
>
> --
> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/05d3d02d-69c7-24a4-c2b2-26bdb53556db%40candelatech.com.

Re: [syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)

[Ben Greear]

On 10/14/24 02:54, Aleksandr Nogikh wrote:
> Hi Ben,
> 
> On Fri, Oct 11, 2024 at 11:50 AM Ben Greear <greearb@candelatech.com> wrote:
>>
>> On 10/10/24 08:19, syzbot wrote:
>>> Hello,
>>>
>>> syzbot found the following issue on:
>>>
>>> HEAD commit:    2a130b7e1fcd Merge tag 'kbuild-fixes-v6.12' of git://git.k..
>>> git tree:       upstream
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1206e79f980000
>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=f38c36a955431c1
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=5506b2556159a1ab6923
>>> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
>>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=155b8327980000
>>
>> This looks like something I saw in 6.11 and 6.10.  My guess was that one of the
>> running processes that lockdep does not print locks for is holding the wiphy mtx.
>>
>> Maybe it would help if syzbot would use sysrq to dump all running tasks to the console, and maybe
>> lockdep could print locks for running processes, even if they are marked as potentially
>> unreliable?
> 
> Thanks for the suggestions!
> 
> We do have an open issue re. SysRq:
> https://github.com/google/syzkaller/issues/4200
> I've noted a +1 to that.
> 
> Regarding the locks -- they are actually already printed in the
> original bug report, under "Showing all locks held in the system:". Or
> did you mean something else?

Notice that some processes say they have locks but do not print them.  Lockep
skips printing locks for running processes that are not the current process.

I have added some local code to try printing them anyway, will see if it helps
any...

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com