syzbot


INFO: task hung in fib6_rules_net_exit_batch (3)

Status: auto-obsoleted due to no activity on 2025/05/05 09:06
Subsystems: net
[Documentation on labels]
First crash: 312d, last: 177d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: task hung in fib6_rules_net_exit_batch 1 2 422d 429d 0/3 auto-obsoleted due to no activity on 2024/09/12 02:11
upstream INFO: task hung in fib6_rules_net_exit_batch (2) net 1 10 408d 432d 0/29 auto-obsoleted due to no activity on 2024/08/06 23:39
upstream INFO: task hung in fib6_rules_net_exit_batch net 1 1 782d 782d 0/29 closed as invalid on 2023/09/07 14:58

Sample crash report:
INFO: task kworker/u8:45:14769 blocked for more than 144 seconds.
      Not tainted 6.14.0-rc1-syzkaller-00020-g0de63bb7d919 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:45   state:D stack:27104 pid:14769 tgid:14769 ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6856
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730
 fib6_rules_net_exit_batch+0x15/0xe0 net/ipv6/fib6_rules.c:600
 ops_exit_list+0x128/0x180 net/core/net_namespace.c:177
 cleanup_net+0x5c6/0xbf0 net/core/net_namespace.c:652
 process_one_work+0x958/0x1b30 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 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>
INFO: task syz.2.2095:14883 blocked for more than 144 seconds.
      Not tainted 6.14.0-rc1-syzkaller-00020-g0de63bb7d919 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.2095      state:D stack:26528 pid:14883 tgid:14876 ppid:5834   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0xf43/0x5890 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6856
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6913
 __mutex_lock_common kernel/locking/mutex.c:662 [inline]
 __mutex_lock+0x6bd/0xb10 kernel/locking/mutex.c:730
 ip_tunnel_init_net+0x1b0/0x6e0 net/ipv4/ip_tunnel.c:1159
 ops_init+0x1df/0x5f0 net/core/net_namespace.c:138
 setup_net+0x21f/0x860 net/core/net_namespace.c:362
 copy_net_ns+0x2b4/0x6c0 net/core/net_namespace.c:516
 create_new_namespaces+0x3ea/0xad0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc0/0x1f0 kernel/nsproxy.c:228
 ksys_unshare+0x45d/0xa40 kernel/fork.c:3342
 __do_sys_unshare kernel/fork.c:3413 [inline]
 __se_sys_unshare kernel/fork.c:3411 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:3411
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f172bf8cda9
RSP: 002b:00007f1729dd5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f172c1a6080 RCX: 00007f172bf8cda9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000080
RBP: 00007f172c00e2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f172c1a6080 R15: 00007ffec0ad1138
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e1bc140 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e1bc140 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e1bc140 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6746
3 locks held by kworker/u8:4/62:
1 lock held by jbd2/sda1-8/5170:
3 locks held by syslogd/5190:
1 lock held by klogd/5197:
4 locks held by udevd/5208:
5 locks held by dhcpcd/5502:
2 locks held by getty/5597:
 #0: ffff88814e0f40a0 (&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:
2 locks held by kworker/1:3/5883:
2 locks held by kworker/0:4/12261:
1 lock held by syz-executor/12323:
2 locks held by kworker/1:0/12479:
2 locks held by kworker/u8:27/14750:
3 locks held by kworker/u8:28/14751:
3 locks held by kworker/u8:31/14754:
3 locks held by kworker/u8:32/14755:
2 locks held by kworker/u8:34/14757:
 #0: ffff88801f3ec148 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211
 #1: ffffc9000c0c7d18 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212
3 locks held by kworker/u8:35/14758:
 #0: ffff8880312b1948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211
 #1: ffffc9000c0b7d18 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212
 #2: ffffffff8fed7ea8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:129 [inline]
 #2: ffffffff8fed7ea8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4730
8 locks held by kworker/u8:37/14760:
3 locks held by kworker/u8:41/14765:
2 locks held by kworker/u8:44/14768:
4 locks held by kworker/u8:45/14769:
 #0: ffff88801bef5948 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211
 #1: ffffc9000b897d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212
 #2: ffffffff8fec1ed0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xca/0xbf0 net/core/net_namespace.c:606
 #3: ffffffff8fed7ea8 (rtnl_mutex){+.+.}-{4:4}, at: fib6_rules_net_exit_batch+0x15/0xe0 net/ipv6/fib6_rules.c:600
3 locks held by kworker/u8:46/14770:
3 locks held by kworker/u8:47/14771:
3 locks held by syz.6.2080/14791:
2 locks held by syz.6.2076/14810:
3 locks held by syz.6.2076/14811:
2 locks held by syz.2.2095/14883:
 #0: ffffffff8fec1ed0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x292/0x6c0 net/core/net_namespace.c:512
 #1: ffffffff8fed7ea8 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x1b0/0x6e0 net/ipv4/ip_tunnel.c:1159
3 locks held by syz.1.2097/14880:
6 locks held by syz.5.2098/14888:
3 locks held by syz-executor/14892:
3 locks held by kworker/1:7/14893:
 #0: ffff88801b080d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12cd/0x1b30 kernel/workqueue.c:3211
 #1: ffffc9000465fd18 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3212
 #2: ffffffff8fed7ea8 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
2 locks held by kworker/0:7/14894:
3 locks held by syz-executor/14897:
2 locks held by kworker/0:10/14900:
2 locks held by dhcpcd/14901:
 #0: ffff8880350d0258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline]
 #0: ffff8880350d0258 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf60 net/packet/af_packet.c:3253
 #1: ffffffff8e1c75b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x282/0x3b0 kernel/rcu/tree_exp.h:302

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.14.0-rc1-syzkaller-00020-g0de63bb7d919 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
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: 14755 Comm: kworker/u8:32 Not tainted 6.14.0-rc1-syzkaller-00020-g0de63bb7d919 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:skb_transport_header_was_set include/linux/skbuff.h:3015 [inline]
RIP: 0010:skb_transport_header include/linux/skbuff.h:3020 [inline]
RIP: 0010:skb_transport_offset include/linux/skbuff.h:3148 [inline]
RIP: 0010:ip6_multipath_l3_keys.constprop.0+0x444/0xbc0 net/ipv6/route.c:2319
Code: 00 00 0f 85 ad 06 00 00 48 81 c4 18 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 93 5d c2 f7 49 8d 8f b6 00 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 ca 48 89 4c 24 20 48 c1 ea 03
RSP: 0018:ffffc90000006b40 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90000006d00 RCX: ffff88803072c5b6
RDX: ffff88803e609e00 RSI: ffffffff89f68f2d RDI: 0000000000000001
RBP: ffffc90000006c80 R08: 0000000000000001 R09: 000000000000003a
R10: 000000000000003a R11: 0000000000000005 R12: 0000000000000000
R13: ffff888027849210 R14: ffffc90000006be8 R15: ffff88803072c500
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a5ecd56e8 CR3: 000000000df80000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 rt6_multipath_hash+0x5f2/0x17f0 net/ipv6/route.c:2480
 ip6_route_input+0xa77/0xc10 net/ipv6/route.c:2594
 ip6_rcv_finish_core.constprop.0+0x1a0/0x5d0 net/ipv6/ip6_input.c:66
 ip6_rcv_finish+0x12c/0x5b0 net/ipv6/ip6_input.c:77
 ip_sabotage_in+0x21b/0x290 net/bridge/br_netfilter_hooks.c:993
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626
 nf_hook.constprop.0+0x42e/0x750 include/linux/netfilter.h:269
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ipv6_rcv+0xa4/0x680 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core+0x12e/0x1e0 net/core/dev.c:5828
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5941
 netif_receive_skb_internal net/core/dev.c:6027 [inline]
 netif_receive_skb+0x13f/0x7b0 net/core/dev.c:6086
 NF_HOOK include/linux/netfilter.h:314 [inline]
 NF_HOOK include/linux/netfilter.h:308 [inline]
 br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70
 br_handle_frame_finish+0xecc/0x1c90 net/bridge/br_input.c:226
 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+0xa81/0x14c0 net/bridge/br_input.c:433
 __netif_receive_skb_core.constprop.0+0xa20/0x4330 net/core/dev.c:5722
 __netif_receive_skb_one_core+0xb1/0x1e0 net/core/dev.c:5826
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5941
 process_backlog+0x443/0x15f0 net/core/dev.c:6289
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7106
 napi_poll net/core/dev.c:7175 [inline]
 net_rx_action+0xa94/0x1010 net/core/dev.c:7297
 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
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 cfg80211_put_bss+0x1b4/0x280 net/wireless/scan.c:3346
 ieee80211_rx_bss_put net/mac80211/scan.c:37 [inline]
 ieee80211_rx_bss_put+0x43/0x60 net/mac80211/scan.c:32
 ieee80211_rx_bss_info net/mac80211/ibss.c:1174 [inline]
 ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1581 [inline]
 ieee80211_ibss_rx_queued_mgmt+0x1ad2/0x3040 net/mac80211/ibss.c:1608
 ieee80211_iface_process_skb net/mac80211/iface.c:1611 [inline]
 ieee80211_iface_work+0xc15/0xf50 net/mac80211/iface.c:1665
 cfg80211_wiphy_work+0x3ed/0x570 net/wireless/core.c:435
 process_one_work+0x958/0x1b30 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3317 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398
 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 (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/04 09:05 upstream 0de63bb7d919 8f267cef .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in fib6_rules_net_exit_batch
2024/12/10 00:40 upstream 7cb1b4663150 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
2024/09/30 02:59 upstream e7ed34365879 ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
2024/09/21 17:43 upstream 1868f9d0260e 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
2025/01/06 09:57 net 8ce4f287524c f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
2024/10/11 22:49 net 1d227fcc7222 cd942402 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
2024/11/04 23:16 net-next ecf99864ea6b 509da429 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
2024/10/21 21:39 net-next 6d858708d465 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce INFO: task hung in fib6_rules_net_exit_batch
* Struck through repros no longer work on HEAD.