[v6.1] INFO: task hung in addrconf_dad_work

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0102425ac76b Linux 6.1.24
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=137355c7c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=cb976cea3176ce66
dashboard link: https://syzkaller.appspot.com/bug?extid=6ab19a6057f9d1b05f25
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c3f0c7c2b742/disk-0102425a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b3bd7fbfc5b/vmlinux-0102425a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b5fd9317ad29/bzImage-0102425a.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6ab19a...@syzkaller.appspotmail.com

INFO: task kworker/1:7:3785 blocked for more than 143 seconds.
Not tainted 6.1.24-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:7 state:D stack:24568 pid:3785 ppid:2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0x132c/0x4330 kernel/sched/core.c:6554
schedule+0xbf/0x180 kernel/sched/core.c:6630
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6689
__mutex_lock_common+0xe2b/0x2520 kernel/locking/mutex.c:679
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
addrconf_dad_work+0xcc/0x16b0 net/ipv6/addrconf.c:4088
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
INFO: task kworker/0:1:1675 blocked for more than 144 seconds.
Not tainted 6.1.24-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:1 state:D stack:24672 pid:1675 ppid:2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0x132c/0x4330 kernel/sched/core.c:6554
schedule+0xbf/0x180 kernel/sched/core.c:6630
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6689
__mutex_lock_common+0xe2b/0x2520 kernel/locking/mutex.c:679
__mutex_lock kernel/locking/mutex.c:747 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:799
addrconf_dad_work+0xcc/0x16b0 net/ipv6/addrconf.c:4088
process_one_work+0x8aa/0x11f0 kernel/workqueue.c:2289
worker_thread+0xa5f/0x1210 kernel/workqueue.c:2436
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:1/11:
#0: ffff888012469138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1:
ffffc90000107d20 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8cf26870 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:510
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8cf27070 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:510
1 lock held by khungtaskd/28:
#0: ffffffff8cf266a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3310:
#0: ffff88814a92e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2177
3 locks held by kworker/u4:6/3759:
#0: ffff888019241938 ((wq_completion)cfg80211){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc9000518fd20 ((work_completion)(&(&rdev->dfs_update_channels_wk)->work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
#2: ffffffff8e08a0c8 (rtnl_mutex){+.+.}-{3:3}, at: cfg80211_dfs_channels_update_work+0xbb/0x610 net/wireless/mlme.c:875
3 locks held by kworker/1:7/3785:
#0: ffff88814a71cd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc900052bfd20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
#2: ffffffff8e08a0c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16b0 net/ipv6/addrconf.c:4088
2 locks held by kworker/u4:9/3930:
#0: ffff888012469138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc90005907d20 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
3 locks held by kworker/1:3/18157:
#0: ffff888012465d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc900d0cb7d20 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
#2: ffffffff8e08a0c8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x90/0xe40 net/wireless/reg.c:2493
4 locks held by kworker/u4:5/23289:
#0: ffff888012606938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc900053cfd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
#2: ffffffff8e07dd10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf1/0xb60 net/core/net_namespace.c:563
#3: ffffffff8e08a0c8 (rtnl_mutex){+.+.}-{3:3}, at: ieee80211_unregister_hw+0x4d/0x220 net/mac80211/main.c:1465
2 locks held by kworker/0:13/13832:
3 locks held by kworker/0:0/32571:
#0: ffff888012464d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc9008a8afd20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
#2: ffffffff8e08a0c8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
3 locks held by kworker/0:1/1675:
#0: ffff88814a71cd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x77a/0x11f0
#1: ffffc900a4cefd20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7bd/0x11f0 kernel/workqueue.c:2264
#2: ffffffff8e08a0c8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16b0 net/ipv6/addrconf.c:4088
2 locks held by dhcpcd/12048:
#0: ffff88804c5fca10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#0: ffff88804c5fca10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:651 [inline]
#0: ffff88804c5fca10 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1370
#1: ffffffff8cf2bc78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#1: ffffffff8cf2bc78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x479/0x8a0 kernel/rcu/tree_exp.h:948
6 locks held by syz-executor.1/13849:
3 locks held by syz-executor.2/13854:
#0: ffff888074867958 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff888074867958 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault arch/x86/mm/fault.c:1369 [inline]
#0: ffff888074867958 (&mm->mmap_lock#2){++++}-{3:3}, at: handle_page_fault arch/x86/mm/fault.c:1519 [inline]
#0: ffff888074867958 (&mm->mmap_lock#2){++++}-{3:3}, at: exc_page_fault+0x182/0x790 arch/x86/mm/fault.c:1575
#1: ffffffff8d024440 (memcg_oom_lock#2){+.+.}-{0:0}, at: mem_cgroup_oom mm/memcontrol.c:1930 [inline]
#1: ffffffff8d024440 (memcg_oom_lock#2){+.+.}-{0:0}, at: try_charge_memcg+0xb28/0x16b0 mm/memcontrol.c:2729
#2: ffffffff8cfc79a8 (oom_lock){+.+.}-{3:3}, at: mem_cgroup_out_of_memory+0xf3/0x3b0 mm/memcontrol.c:1696

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.24-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1b0/0x3f0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xf18/0xf60 kernel/hung_task.c:377
kthread+0x268/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 13849 Comm: syz-executor.1 Not tainted 6.1.24-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
RIP: 0010:lookup_object lib/debugobjects.c:195 [inline]
RIP: 0010:debug_object_deactivate+0xa4/0x3f0 lib/debugobjects.c:741
Code: a7 fd 4c 89 34 24 48 8b 1b 45 31 f6 eb 06 48 8b 1b 41 ff c6 48 85 db 74 38 4c 8d 7b 18 4d 89 fd 49 c1 ed 03 43 80 7c 25 00 00 <74> 08 4c 89 ff e8 02 98 a7 fd 49 39 2f 74 7d 48 89 d8 48 c1 e8 03
RSP: 0018:ffffc900001e0bf0 EFLAGS: 00000046
RAX: 1ffffffff2395e82 RBX: ffff8880b435e310 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffc900001e0ac0
RBP: ffff8880526b5720 R08: dffffc0000000000 R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff1101686bc65 R14: 0000000000000000 R15: ffff8880b435e328
FS: 000055555572d400(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6bb2f831b8 CR3: 00000000b30c1000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
debug_timer_deactivate kernel/time/timer.c:787 [inline]
debug_deactivate kernel/time/timer.c:831 [inline]
detach_timer+0x26/0x380 kernel/time/timer.c:878
expire_timers kernel/time/timer.c:1508 [inline]
__run_timers+0x60c/0x890 kernel/time/timer.c:1790
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1803
__do_softirq+0x2e9/0xa4c kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x155/0x240 kernel/softirq.c:650
irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
sysvec_apic_timer_interrupt+0x91/0xb0 arch/x86/kernel/apic/apic.c:1107
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:console_trylock_spinning+0x3ad/0x450 kernel/printk/printk.c:1919
Code: 0f 84 4c ff ff ff e8 c2 56 1c 00 fb 31 db eb 41 e8 b8 56 1c 00 e8 33 ca 10 09 4d 85 ed 74 cd e8 a9 56 1c 00 fb bb 01 00 00 00 <48> c7 c7 40 28 e0 8c 31 f6 ba 01 00 00 00 31 c9 41 b8 01 00 00 00
RSP: 0018:ffffc900a24073c0 EFLAGS: 00000293
RAX: ffffffff816d2a57 RBX: 0000000000000001 RCX: ffff8880227d0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900a2407488 R08: ffffffff816d2a10 R09: fffffbfff204e053
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92014480e78
R13: 0000000000000200 R14: 0000000000000046 R15: dffffc0000000000
vprintk_emit+0xb8/0x1f0 kernel/printk/printk.c:2267
_printk+0xd1/0x111 kernel/printk/printk.c:2289
mem_cgroup_print_oom_meminfo+0x16d/0x330
dump_header+0x112/0x9c0 mm/oom_kill.c:462
oom_kill_process+0xf8/0x520 mm/oom_kill.c:1036
out_of_memory+0xf30/0x12f0 mm/oom_kill.c:1174
mem_cgroup_out_of_memory+0x25f/0x3b0 mm/memcontrol.c:1706
mem_cgroup_oom mm/memcontrol.c:1936 [inline]
try_charge_memcg+0xcaa/0x16b0 mm/memcontrol.c:2729
try_charge mm/memcontrol.c:2823 [inline]
charge_memcg+0x116/0x3f0 mm/memcontrol.c:6894
__mem_cgroup_charge+0x23/0x80 mm/memcontrol.c:6915
mem_cgroup_charge include/linux/memcontrol.h:667 [inline]
do_anonymous_page mm/memory.c:4127 [inline]
handle_pte_fault mm/memory.c:4962 [inline]
__handle_mm_fault mm/memory.c:5106 [inline]
handle_mm_fault+0x2bac/0x5140 mm/memory.c:5227
do_user_addr_fault arch/x86/mm/fault.c:1428 [inline]
handle_page_fault arch/x86/mm/fault.c:1519 [inline]
exc_page_fault+0x58d/0x790 arch/x86/mm/fault.c:1575
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x7f0a78c2beda
Code: 30 48 8b 34 24 48 85 f6 74 17 8b 44 24 18 0f c8 89 c0 48 89 44 24 18 48 83 fe 01 0f 85 a1 01 00 00 48 8b 44 24 10 8b 74 24 18 <89> 30 e9 d2 fc ff ff 48 8b 44 24 10 8b 10 48 8b 04 24 48 85 c0 0f
RSP: 002b:00007fff1ad4e640 EFLAGS: 00010246
RAX: 0000000020000440 RBX: 0000000000000000 RCX: 0000000000000000
RDX: a475b49d67229004 RSI: 0000000000000011 RDI: 000055555572d2e8
RBP: 00007fff1ad4e738 R08: 0000000000000000 R09: 0000000000000000
R10: 00007f0a788002a0 R11: 00000000000a0da2 R12: 000000000035f181
R13: 00007fff1ad4e760 R14: 00007fff1ad4e780 R15: 0000000000000032
</TASK>


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.