syzbot


INFO: task hung in linkwatch_event (3)

Status: upstream: reported on 2023/01/03 10:49
Reported-by: syzbot+9c9a5d5a6c1e5022ab3e@syzkaller.appspotmail.com
First crash: 532d, last: 531d
Similar bugs (13)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-414 INFO: task hung in linkwatch_event C 7 1676d 1896d 0/1 public: reported C repro on 2019/04/10 16:14
linux-4.14 INFO: task hung in linkwatch_event (2) 1 697d 697d 0/1 auto-obsoleted due to no activity on 2022/11/19 11:58
android-44 INFO: task hung in linkwatch_event 6 2112d 2257d 0/2 auto-closed as invalid on 2019/03/05 13:11
linux-5.15 INFO: task hung in linkwatch_event 58 23h18m 159d 0/3 upstream: reported on 2024/01/11 11:32
upstream INFO: task hung in linkwatch_event net C 82 1704d 2316d 0/27 closed as dup on 2018/02/14 15:33
linux-4.14 INFO: task hung in linkwatch_event 5 1380d 1507d 0/1 auto-closed as invalid on 2021/01/05 01:42
linux-4.19 INFO: task hung in linkwatch_event (2) C error 217 471d 1559d 0/1 upstream: reported C repro on 2020/03/11 20:12
upstream INFO: task hung in linkwatch_event (2) net C done done 1033 785d 1511d 20/27 fixed on 2022/05/13 11:13
linux-4.19 INFO: task hung in linkwatch_event 3 1713d 1827d 0/1 auto-closed as invalid on 2020/02/07 01:11
upstream INFO: task hung in linkwatch_event (3) net 1513 36m 574d 0/27 upstream: reported on 2022/11/22 17:04
android-49 INFO: task hung in linkwatch_event 13 1875d 1892d 0/3 auto-closed as invalid on 2019/10/25 08:50
linux-6.1 INFO: task hung in linkwatch_event (2) 26 6h08m 29d 0/3 upstream: reported on 2024/05/20 16:52
linux-6.1 INFO: task hung in linkwatch_event 2 317d 433d 0/3 auto-obsoleted due to no activity on 2023/11/14 00:59

Sample crash report:
INFO: task kworker/0:1:24 blocked for more than 140 seconds.
      Not tainted 4.14.302-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:1     D26576    24      2 0x80000000
Workqueue: events linkwatch_event
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 linkwatch_event+0xa/0x50 net/core/link_watch.c:236
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:406
INFO: task kworker/1:2:4626 blocked for more than 140 seconds.
      Not tainted 4.14.302-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:2     D27584  4626      2 0x80000000
Workqueue: events_power_efficient reg_check_chans_work
Call Trace:
 context_switch kernel/sched/core.c:2811 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3387
 schedule+0x8d/0x1b0 kernel/sched/core.c:3431
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3489
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x669/0x1310 kernel/locking/mutex.c:893
 reg_check_chans_work+0x77/0xd00 net/wireless/reg.c:1655
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:406

Showing all locks held in the system:
3 locks held by kworker/0:1/24:
 #0:  ("events"){+.+.}, at: [<ffffffff81366130>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((linkwatch_work).work){+.+.}, at: [<ffffffff81366166>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (rtnl_mutex){+.+.}, at: [<ffffffff85c956ea>] linkwatch_event+0xa/0x50 net/core/link_watch.c:236
1 lock held by khungtaskd/1532:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8702b3a4>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
3 locks held by kworker/1:2/4626:
 #0:  ("events_power_efficient"){+.+.}, at: [<ffffffff81366130>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((reg_check_chans).work){+.+.}, at: [<ffffffff81366166>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (rtnl_mutex){+.+.}, at: [<ffffffff869eb7e7>] reg_check_chans_work+0x77/0xd00 net/wireless/reg.c:1655
1 lock held by in:imklog/7699:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff818d8f8b>] __fdget_pos+0x1fb/0x2b0 fs/file.c:819
3 locks held by kworker/1:3/7706:
 #0:  ("%s"("ipv6_addrconf")){+.+.}, at: [<ffffffff81366130>] process_one_work+0x6b0/0x14a0 kernel/workqueue.c:2088
 #1:  ((addr_chk_work).work){+.+.}, at: [<ffffffff81366166>] process_one_work+0x6e6/0x14a0 kernel/workqueue.c:2092
 #2:  (rtnl_mutex){+.+.}, at: [<ffffffff8637510a>] addrconf_verify_work+0xa/0x20 net/ipv6/addrconf.c:4421
1 lock held by syz-fuzzer/8008:
 #0:  (&mm->mmap_sem){++++}, at: [<ffffffff817977cf>] SYSC_madvise mm/madvise.c:827 [inline]
 #0:  (&mm->mmap_sem){++++}, at: [<ffffffff817977cf>] SyS_madvise+0x19f/0x18c0 mm/madvise.c:791
1 lock held by syz-fuzzer/8009:
 #0:  (&mm->mmap_sem){++++}, at: [<ffffffff812428a8>] __do_page_fault+0x7b8/0xad0 arch/x86/mm/fault.c:1378
3 locks held by syz-executor.4/8015:
 #0:  (&hdev->req_lock){+.+.}, at: [<ffffffff8661cb38>] hci_dev_do_close+0xa8/0xd80 net/bluetooth/hci_core.c:1589
 #1:  (&hdev->lock){+.+.}, at: [<ffffffff8661ccf4>] hci_dev_do_close+0x264/0xd80 net/bluetooth/hci_core.c:1628
 #2:  (uevent_sock_mutex){+.+.}, at: [<ffffffff86fece05>] kobject_uevent_env+0x755/0xf30 lib/kobject_uevent.c:460
3 locks held by syz-executor.1/8030:
 #0:  (&hdev->req_lock){+.+.}, at: [<ffffffff8661cb38>] hci_dev_do_close+0xa8/0xd80 net/bluetooth/hci_core.c:1589
 #1:  (&hdev->lock){+.+.}, at: [<ffffffff8661ccf4>] hci_dev_do_close+0x264/0xd80 net/bluetooth/hci_core.c:1628
 #2:  (uevent_sock_mutex){+.+.}, at: [<ffffffff86fece05>] kobject_uevent_env+0x755/0xf30 lib/kobject_uevent.c:460
3 locks held by syz-executor.2/9664:
 #0:  (&hdev->req_lock){+.+.}, at: [<ffffffff8661cb38>] hci_dev_do_close+0xa8/0xd80 net/bluetooth/hci_core.c:1589
 #1:  (&hdev->lock){+.+.}, at: [<ffffffff8661ccf4>] hci_dev_do_close+0x264/0xd80 net/bluetooth/hci_core.c:1628
 #2:  (uevent_sock_mutex){+.+.}, at: [<ffffffff86fece05>] kobject_uevent_env+0x755/0xf30 lib/kobject_uevent.c:460
3 locks held by syz-executor.5/9678:
 #0:  (vlan_ioctl_mutex){+.+.}, at: [<ffffffff85bd35e3>] sock_ioctl+0x313/0x4c0 net/socket.c:1047
 #1:  (rtnl_mutex){+.+.}, at: [<ffffffff8689f7ea>] vlan_ioctl_handler+0x9a/0xcb0 net/8021q/vlan.c:518
 #2:  (uevent_sock_mutex){+.+.}, at: [<ffffffff86fece05>] kobject_uevent_env+0x755/0xf30 lib/kobject_uevent.c:460
3 locks held by syz-executor.3/9675:
 #0:  (&hdev->req_lock){+.+.}, at: [<ffffffff8661cb38>] hci_dev_do_close+0xa8/0xd80 net/bluetooth/hci_core.c:1589
 #1:  (&hdev->lock){+.+.}, at: [<ffffffff8661ccf4>] hci_dev_do_close+0x264/0xd80 net/bluetooth/hci_core.c:1628
 #2:  (uevent_sock_mutex){+.+.}, at: [<ffffffff86fece05>] kobject_uevent_env+0x755/0xf30 lib/kobject_uevent.c:460

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

NMI backtrace for cpu 0
CPU: 0 PID: 1532 Comm: khungtaskd Not tainted 4.14.302-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5b9/0xb40 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:406
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 18 Comm: kworker/1:0 Not tainted 4.14.302-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: events_power_efficient fb_flashcursor
task: ffff8880b54aa4c0 task.stack: ffff8880b54b8000
RIP: 0010:unwind_next_frame+0xc8a/0x17d0 arch/x86/kernel/unwind_orc.c:423
RSP: 0018:ffff8880ba507998 EFLAGS: 00000246
RAX: ffff8880b54bff18 RBX: 1ffff110174a0f3a RCX: ffffffff8a6b7114
RDX: ffff8880ba507aa0 RSI: 0000000000000000 RDI: ffff8880ba507a58
RBP: 0000000000000001 R08: ffffffff8a6b7118 R09: ffffffff8a6b7119
R10: 000000000000bba0 R11: 0000000000000001 R12: ffff8880ba507a8d
R13: ffff8880ba507a90 R14: ffff8880ba507aa8 R15: ffff8880ba507a58
FS:  0000000000000000(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056062ff83160 CR3: 000000009c59d000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __save_stack_trace+0x90/0x160 arch/x86/kernel/stacktrace.c:44
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc_node mm/slab.c:3333 [inline]
 kmem_cache_alloc_node_trace+0x13d/0x400 mm/slab.c:3659
 __do_kmalloc_node mm/slab.c:3681 [inline]
 __kmalloc_node_track_caller+0x38/0x70 mm/slab.c:3696
 __kmalloc_reserve net/core/skbuff.c:137 [inline]
 __alloc_skb+0x96/0x510 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:980 [inline]
 bcm_can_tx+0x1c1/0x690 net/can/bcm.c:301
 bcm_tx_timeout_tsklet+0x179/0x320 net/can/bcm.c:428
 tasklet_action+0x195/0x340 kernel/softirq.c:513
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x193/0x240 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:796
 </IRQ>
RIP: 0010:lock_acquire+0x1f5/0x3f0 kernel/locking/lockdep.c:4002
RSP: 0018:ffff8880b54bfcc0 EFLAGS: 00000296 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff11e13d9 RBX: ffff8880b54aa4c0 RCX: 8e3b9771c4acfc2e
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000282
RBP: ffffffff88f6f3e0 R08: 0000000000000001 R09: 0000000000048006
R10: ffff8880b54aad98 R11: ffff8880b54aa4c0 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001
 __down_trylock_console_sem+0x11f/0x1e0 kernel/printk/printk.c:235
 console_trylock+0x14/0x70 kernel/printk/printk.c:2246
 fb_flashcursor+0x40/0x3f0 drivers/video/fbdev/core/fbcon.c:356
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2117
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2251
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:406
Code: e8 3c 90 5b 00 48 8b 4c 24 08 e9 71 fe ff ff 48 8b 44 24 58 4c 89 ff 4c 89 4c 24 30 48 8b 54 24 08 48 89 4c 24 28 4c 89 44 24 20 <48> 8d 70 f8 48 89 44 24 18 e8 c8 f1 ff ff 84 c0 0f 84 5a f7 ff 

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/01/04 07:33 linux-4.14.y c4215ee4771b 1dac8c7a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-4-14 INFO: task hung in linkwatch_event
2023/01/03 10:49 linux-4.14.y c4215ee4771b f0036e18 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-4-14 INFO: task hung in linkwatch_event
* Struck through repros no longer work on HEAD.