Message-ID: <66fdaacc.050a0220.40bef.0023.GAE@google.com>
Date: Wed, 02 Oct 2024 13:19:24 -0700
From: syzbot <syzbot+7da6c19dc528c2ebc612@...kaller.appspotmail.com>
To: Jason@...c4.com, davem@...emloft.net, edumazet@...gle.com, jason@...c4.com, 
	kuba@...nel.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org, 
	pabeni@...hat.com, syzkaller-bugs@...glegroups.com, wireguard@...ts.zx2c4.com
Subject: Re: [syzbot] [wireguard?] INFO: task hung in wg_destruct (2)

syzbot has found a reproducer for the following issue on:

HEAD commit:    e32cde8d2bd7 Merge tag 'sched_ext-for-6.12-rc1-fixes-1' of..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1670339f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=286b31f2cf1c36b5
dashboard link: https://syzkaller.appspot.com/bug?extid=7da6c19dc528c2ebc612
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=146ae580580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f7f2dc1bf47b/disk-e32cde8d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/063e4eafb554/vmlinux-e32cde8d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7ce38bae7b74/bzImage-e32cde8d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7da6c19dc528c2ebc612@...kaller.appspotmail.com

INFO: task kworker/u8:5:1092 blocked for more than 145 seconds.
      Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:5    state:D stack:22072 pid:1092  tgid:1092  ppid:2      flags:0x00004000
Workqueue: netns cleanup_net
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
 wg_destruct+0x25/0x2e0 drivers/net/wireguard/device.c:246
 netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10805
 default_device_exit_batch+0xa24/0xaa0 net/core/dev.c:11945
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:626
 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>
INFO: task dhcpcd:4899 blocked for more than 153 seconds.
      Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:20352 pid:4899  tgid:4899  ppid:4898   flags:0x00000002
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
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnl_dumpit+0x99/0x200 net/core/rtnetlink.c:6505
 netlink_dump+0x647/0xd80 net/netlink/af_netlink.c:2325
 __netlink_dump_start+0x5a2/0x790 net/netlink/af_netlink.c:2440
 netlink_dump_start include/linux/netlink.h:339 [inline]
 rtnetlink_dump_start net/core/rtnetlink.c:6535 [inline]
 rtnetlink_rcv_msg+0xb3d/0xcf0 net/core/rtnetlink.c:6602
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:729 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:744
 __sys_sendto+0x39b/0x4f0 net/socket.c:2209
 __do_sys_sendto net/socket.c:2221 [inline]
 __se_sys_sendto net/socket.c:2217 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2217
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f33cf298ad7
RSP: 002b:00007ffdc403cb38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007ffdc403dc60 RCX: 00007f33cf298ad7
RDX: 0000000000000014 RSI: 00007ffdc403db80 RDI: 0000000000000013
RBP: 00007ffdc403dbf0 R08: 00007ffdc403db64 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000012
R13: 00007ffdc403db64 R14: 00007ffdc403db80 R15: 0000000000000105
 </TASK>

Showing all locks held in the system:
6 locks held by kworker/0:0/8:
1 lock held by khungtaskd/30:
 #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
3 locks held by kworker/u8:3/52:
5 locks held by kworker/u9:0/54:
 #0: ffff888064184948 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff888064184948 ((wq_completion)hci2){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90000bf7d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90000bf7d00 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffff888028a88d80 (&hdev->req_lock){+.+.}-{3:3}, at: hci_cmd_sync_work+0x1ec/0x400 net/bluetooth/hci_sync.c:327
 #3: ffff888028a88078 (&hdev->lock){+.+.}-{3:3}, at: hci_abort_conn_sync+0x1ea/0xde0 net/bluetooth/hci_sync.c:5567
 #4: ffffffff8fe3dfa8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_connect_cfm include/net/bluetooth/hci_core.h:1957 [inline]
 #4: ffffffff8fe3dfa8 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_failed+0x15d/0x300 net/bluetooth/hci_conn.c:1262
1 lock held by kswapd0/88:
1 lock held by kswapd1/89:
3 locks held by kworker/1:2/937:
 #0: ffff88801ac81948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801ac81948 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90003907d00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90003907d00 ((reg_check_chans).work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcd1748 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x99/0xfd0 net/wireless/reg.c:2480
4 locks held by kworker/u8:5/1092:
 #0: ffff88801baed948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88801baed948 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc90003e07d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc90003e07d00 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcc4c50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x16a/0xcc0 net/core/net_namespace.c:580
 #3: ffffffff8fcd1748 (rtnl_mutex){+.+.}-{3:3}, at: wg_destruct+0x25/0x2e0 drivers/net/wireguard/device.c:246
3 locks held by kworker/u8:6/2919:
3 locks held by kworker/u8:8/3822:
 #0: ffff88802d6e7148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline]
 #0: ffff88802d6e7148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1850 kernel/workqueue.c:3310
 #1: ffffc9000bd0fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline]
 #1: ffffc9000bd0fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1850 kernel/workqueue.c:3310
 #2: ffffffff8fcd1748 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd0/0x16f0 net/ipv6/addrconf.c:4196
2 locks held by syslogd/4667:
1 lock held by klogd/4674:
4 locks held by udevd/4685:
2 locks held by dhcpcd/4899:
 #0: ffff8880245f86c8 (nlk_cb_mutex-ROUTE){+.+.}-{3:3}, at: __netlink_dump_start+0x119/0x790 net/netlink/af_netlink.c:2404


---
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.

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