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

From: Aleksandr Nogikh
Date: Mon Oct 14 2024 - 05:54:31 EST

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In reply to: Ben Greear: "Re: [syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)"
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Hi Ben,

On Fri, Oct 11, 2024 at 11:50 AM Ben Greear <greearb@xxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > 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@xxxxxxxxxxxxxxx>
> Candela Technologies Inc http://www.candelatech.com
>
>
> --
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Next message: Kent Gibson: "Re: [PATCH v2 5/6] gpiolib: switch the line state notifier to atomic"
Previous message: Vladimir Murzin: "Re: [PATCH] ARM: NOMMU: Fix exc_ret for stack frame type"
In reply to: Ben Greear: "Re: [syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)"
Next in thread: Ben Greear: "Re: [syzbot] [wireless?] INFO: task hung in cfg80211_event_work (4)"
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