linux-kernel - [syzbot] [net?] INFO: task hung in nsim

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Date: Fri, 31 May 2024 04:16:20 -0700
From: syzbot <syzbot+8141dcbd23a8f857798a@...kaller.appspotmail.com>
To: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, 
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org, pabeni@...hat.com, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] INFO: task hung in nsim_destroy (4)

Hello,

syzbot found the following issue on:

HEAD commit:    4a4be1ad3a6e Revert "vfs: Delete the associated dentry whe..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14e37be6980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=238430243a58f702
dashboard link: https://syzkaller.appspot.com/bug?extid=8141dcbd23a8f857798a
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b1ea85ab1f5b/disk-4a4be1ad.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/681d06438c4b/vmlinux-4a4be1ad.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9f422d33e089/bzImage-4a4be1ad.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8141dcbd23a8f857798a@...kaller.appspotmail.com

INFO: task kworker/u8:10:2466 blocked for more than 143 seconds.
      Not tainted 6.10.0-rc1-syzkaller-00027-g4a4be1ad3a6e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:10   state:D stack:24624 pid:2466  tgid:2466  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0xf15/0x5d00 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
 nsim_destroy+0x6f/0x6a0 drivers/net/netdevsim/netdev.c:772
 __nsim_dev_port_del+0x189/0x240 drivers/net/netdevsim/dev.c:1425
 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1437 [inline]
 nsim_dev_reload_destroy+0x108/0x4d0 drivers/net/netdevsim/dev.c:1658
 nsim_dev_reload_down+0x6e/0xd0 drivers/net/netdevsim/dev.c:965
 devlink_reload+0x19a/0x7c0 net/devlink/dev.c:461
 devlink_pernet_pre_exit+0x1a1/0x2b0 net/devlink/core.c:509
 ops_pre_exit_list net/core/net_namespace.c:163 [inline]
 cleanup_net+0x488/0xbf0 net/core/net_namespace.c:620
 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: task kworker/1:4:5158 blocked for more than 143 seconds.
      Not tainted 6.10.0-rc1-syzkaller-00027-g4a4be1ad3a6e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:4     state:D stack:24768 pid:5158  tgid:5158  ppid:2      flags:0x00004000
Workqueue: events linkwatch_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0xf15/0x5d00 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6837
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6894
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752
 linkwatch_event+0x51/0xc0 net/core/link_watch.c:276
 process_one_work+0x9fb/0x1b60 kernel/workqueue.c:3231
 process_scheduled_works kernel/workqueue.c:3312 [inline]
 worker_thread+0x6c8/0xf70 kernel/workqueue.c:3393
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 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/30:
 #0: ffffffff8dbb18e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8dbb18e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8dbb18e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614


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