syzbot


INFO: task hung in ip6mr_net_exit_batch (3)

Status: auto-obsoleted due to no activity on 2025/06/18 09:05
Subsystems: net
[Documentation on labels]
First crash: 172d, last: 136d
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ip6mr_net_exit_batch (2) net 1 8 286d 433d 0/29 auto-obsoleted due to no activity on 2025/01/20 02:05
upstream INFO: task hung in ip6mr_net_exit_batch net 1 1 755d 755d 0/29 closed as invalid on 2023/09/07 14:36

Sample crash report:
INFO: task kworker/u8:1:13 blocked for more than 144 seconds.
      Not tainted 6.14.0-rc7-syzkaller-00074-ga7f2e10ecd8f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:1    state:D stack:23984 pid:13    tgid:13    ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6857
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6914
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730
 ip6mr_net_exit_batch+0x15/0xa0 net/ipv6/ip6mr.c:1386
 ops_exit_list+0x128/0x180 net/core/net_namespace.c:177
 cleanup_net+0x5c6/0xb30 net/core/net_namespace.c:652
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 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 kthreadd/2:
3 locks held by kworker/0:0/9:
 #0: ffff88801b081d48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
 #1: ffffc900000e7d18 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
 #2: ffffffff8fefa3e8 (rtnl_mutex){+.+.}-{4:4}, at: reg_check_chans_work+0x84/0x1130 net/wireless/reg.c:2481
4 locks held by kworker/0:1/10:
3 locks held by kworker/u8:0/12:
4 locks held by kworker/u8:1/13:
 #0: ffff88801bef6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
 #1: ffffc90000127d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
 #2: ffffffff8fee46d0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xca/0xb30 net/core/net_namespace.c:606
 #3: ffffffff8fefa3e8 (rtnl_mutex){+.+.}-{4:4}, at: ip6mr_net_exit_batch+0x15/0xa0 net/ipv6/ip6mr.c:1386
1 lock held by khungtaskd/31:
 #0: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1bd140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746
1 lock held by kworker/R-write/33:
3 locks held by kworker/u8:2/36:
3 locks held by kworker/u8:3/53:
3 locks held by kworker/u8:4/62:
3 locks held by kworker/u8:5/1086:
3 locks held by kworker/u8:6/1108:
5 locks held by kworker/0:2/1206:
4 locks held by kworker/1:2/3078:
3 locks held by kworker/R-ipv6_/3169:
 #0: ffff888030a3b148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
 #1: ffffc9000bda7cb0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
 #2: ffffffff8fefa3e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:129 [inline]
 #2: ffffffff8fefa3e8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4733
2 locks held by kworker/R-bat_e/3399:
3 locks held by kworker/u8:7/3806:
1 lock held by syslogd/5190:
1 lock held by klogd/5197:
2 locks held by udevd/5208:
1 lock held by dhcpcd/5501:
3 locks held by dhcpcd/5502:
2 locks held by getty/5598:
 #0: ffff8880352ca0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211
1 lock held by syz-executor/5825:
3 locks held by syz-executor/5834:
3 locks held by kworker/0:3/5837:
 #0: ffff88801b081d48 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
 #1: ffffc90003fafd18 ((crda_timeout).work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
 #2: ffffffff8fefa3e8 (rtnl_mutex){+.+.}-{4:4}, at: crda_timeout_work+0x15/0x50 net/wireless/reg.c:541
1 lock held by syz-executor/5839:
1 lock held by syz-executor/5841:
1 lock held by kworker/R-wg-cr/5872:
 #0: ffffffff8e076608 (wq_pool_attach_mutex){+.+.}-{4:4}, at: worker_detach_from_pool kernel/workqueue.c:2736 [inline]
 #0: ffffffff8e076608 (wq_pool_attach_mutex){+.+.}-{4:4}, at: rescuer_thread+0x836/0xe80 kernel/workqueue.c:3529
5 locks held by kworker/0:4/5877:
4 locks held by kworker/0:5/5878:
4 locks held by kworker/0:6/5879:
 #0: ffff88801b080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1293/0x1ba0 kernel/workqueue.c:3213
 #1: ffffc9000428fd18 (reg_work){+.+.}-{0:0}, at: process_one_work+0x921/0x1ba0 kernel/workqueue.c:3214
 #2: ffffffff8fefa3e8 (rtnl_mutex){+.+.}-{4:4}, at: reg_todo+0x1c/0x910 net/wireless/reg.c:3217
 #3: ffff8880133a8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6061 [inline]
 #3: ffff8880133a8768 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: reg_process_self_managed_hints+0x95/0x1f0 net/wireless/reg.c:3207
2 locks held by kworker/1:3/5880:
4 locks held by kworker/1:4/5898:
1 lock held by syz.0.5/5921:
4 locks held by syz.2.10/5944:
3 locks held by kworker/u8:8/5945:
3 locks held by kworker/u8:9/5947:
4 locks held by kworker/u8:10/5948:
3 locks held by kworker/u8:11/5950:
2 locks held by udevd/5951:
3 locks held by kworker/0:8/5952:
3 locks held by kworker/1:8/5954:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.14.0-rc7-syzkaller-00074-ga7f2e10ecd8f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:236 [inline]
 watchdog+0xf62/0x12b0 kernel/hung_task.c:399
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1206 Comm: kworker/0:2 Not tainted 6.14.0-rc7-syzkaller-00074-ga7f2e10ecd8f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:80 [inline]
RIP: 0010:__orc_find+0x68/0xf0 arch/x86/kernel/unwind_orc.c:102
Code: 8d 6b 04 49 89 df 49 39 ec 72 4e 4c 89 e2 48 29 ea 48 89 d6 48 c1 ea 3f 48 c1 fe 02 48 01 f2 48 d1 fa 48 8d 5c 95 00 48 89 da <48> c1 ea 03 0f b6 34 0a 48 89 da 83 e2 07 83 c2 03 40 38 f2 7c 05
RSP: 0018:ffffc90000006e78 EFLAGS: 00000203
RAX: ffffffff919335fc RBX: ffffffff90dc42b4 RCX: dffffc0000000000
RDX: ffffffff90dc42b4 RSI: 0000000000000003 RDI: ffffffff90dc429c
RBP: ffffffff90dc42b0 R08: ffffffff91933674 R09: ffffffff91850ec6
R10: ffffc90000006f28 R11: 000000000009267b R12: ffffffff90dc42bc
R13: ffffffff8a267b6e R14: ffffffff90dc429c R15: ffffffff90dc42ac
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056542680a108 CR3: 000000006b3dc000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
 unwind_next_frame+0x2be/0x20c0 arch/x86/kernel/unwind_orc.c:494
 arch_stack_walk+0x95/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x95/0xd0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4115 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 kmem_cache_alloc_noprof+0x226/0x3d0 mm/slub.c:4171
 skb_clone+0x190/0x3f0 net/core/skbuff.c:1994
 deliver_clone+0x3f/0xa0 net/bridge/br_forward.c:125
 maybe_deliver+0xa7/0x120 net/bridge/br_forward.c:190
 br_flood+0x17b/0x5e0 net/bridge/br_forward.c:237
 br_handle_frame_finish+0xea2/0x1c90 net/bridge/br_input.c:220
 br_nf_hook_thresh+0x303/0x410 net/bridge/br_netfilter_hooks.c:1170
 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x3ce/0x8c0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:282 [inline]
 br_handle_frame+0xad7/0x14a0 net/bridge/br_input.c:433
 __netif_receive_skb_core.constprop.0+0xa20/0x4330 net/core/dev.c:5790
 __netif_receive_skb_one_core+0xb1/0x1e0 net/core/dev.c:5894
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6009
 process_backlog+0x443/0x15f0 net/core/dev.c:6357
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7191
 napi_poll net/core/dev.c:7260 [inline]
 net_rx_action+0xa94/0x1010 net/core/dev.c:7382
 handle_softirqs+0x213/0x8f0 kernel/softirq.c:561
 do_softirq kernel/softirq.c:462 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:449
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:389
 neigh_periodic_work+0x767/0xcb0 net/core/neighbour.c:968
 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3400
 kthread+0x3af/0x750 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/20 08:58 upstream a7f2e10ecd8f 9209bc22 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ip6mr_net_exit_batch
2025/03/14 14:50 net 4003c9e78778 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in ip6mr_net_exit_batch
2025/02/12 16:40 net-next 4e41231249f4 b27c2402 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in ip6mr_net_exit_batch
* Struck through repros no longer work on HEAD.