syzbot


INFO: rcu detected stall in tun_chr_close (7)

Status: auto-obsoleted due to no activity on 2025/11/04 06:54
Subsystems: mm net
[Documentation on labels]
First crash: 176d, last: 96d
Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in tun_chr_close (3) netfilter 1 1 1932d 1932d 0/29 auto-closed as invalid on 2020/10/25 04:38
upstream INFO: rcu detected stall in tun_chr_close (2) netfilter 1 1 2073d 2072d 0/29 closed as invalid on 2020/05/30 17:14
upstream INFO: rcu detected stall in tun_chr_close (4) bpf net 1 3 1392d 1462d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in tun_chr_close net 1 13 2527d 2607d 0/29 auto-closed as invalid on 2019/06/08 11:01
linux-5.15 INFO: rcu detected stall in tun_chr_close (2) 1 1 429d 429d 0/3 auto-obsoleted due to no activity on 2024/12/15 18:42
linux-5.15 INFO: rcu detected stall in tun_chr_close 1 1 666d 666d 0/3 auto-obsoleted due to no activity on 2024/04/23 00:30
upstream INFO: rcu detected stall in tun_chr_close (5) net 1 1 890d 890d 0/29 auto-obsoleted due to no activity on 2023/09/01 17:23
upstream INFO: rcu detected stall in tun_chr_close (6) net mm 1 19 273d 511d 0/29 auto-obsoleted due to no activity on 2025/05/11 04:14
android-5-15 BUG: soft lockup in tun_chr_close 1 3 538d 568d 0/2 auto-obsoleted due to no activity on 2024/08/19 06:38

Sample crash report:
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5807/1:b..l P20328/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=100269, q=286 ncpus=2)
task:syz.5.4053      state:R  running task     stack:25976 pid:20328 tgid:20317 ppid:19152  task_flags:0x40044c flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x16d/0x2390 arch/x86/kernel/unwind_orc.c:494
Code: d8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 45 1b 00 00 f6 03 03 0f 85 e4 17 00 00 49 8d 5e 35 48 89 d8 48 c1 e8 03 48 89 44 24 28 <0f> b6 04 28 84 c0 0f 85 3c 1b 00 00 4c 89 6c 24 50 4c 89 64 24 20
RSP: 0018:ffffc9000ef96d38 EFLAGS: 00000a03
RAX: 1ffff92001df2dc7 RBX: ffffc9000ef96e3d RCX: f6f7c8b32e283d00
RDX: 0000000000000000 RSI: ffffffff8bc12060 RDI: ffffffff8bc12020
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8171ca05 R12: 1ffff92001df2dc1
R13: ffffc9000ef96e58 R14: ffffc9000ef96e08 R15: ffffffff8171ca05
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1258 [inline]
 __free_frozen_pages+0xb05/0xcd0 mm/page_alloc.c:2721
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f7/0x400 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0 mm/slub.c:4248
 __alloc_skb+0x112/0x2d0 net/core/skbuff.c:658
 alloc_skb include/linux/skbuff.h:1340 [inline]
 alloc_uevent_skb+0x7d/0x230 lib/kobject_uevent.c:289
 uevent_net_broadcast_tagged lib/kobject_uevent.c:352 [inline]
 kobject_uevent_net_broadcast+0x184/0x560 lib/kobject_uevent.c:413
 kobject_uevent_env+0x55b/0x8c0 lib/kobject_uevent.c:608
 __kobject_del+0xd2/0x300 lib/kobject.c:601
 kobject_cleanup lib/kobject.c:680 [inline]
 kobject_release lib/kobject.c:720 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x243/0x480 lib/kobject.c:737
 netdev_queue_update_kobjects+0x5db/0x6c0 net/core/net-sysfs.c:2052
 remove_queue_kobjects net/core/net-sysfs.c:2149 [inline]
 netdev_unregister_kobject+0x11f/0x450 net/core/net-sysfs.c:2304
 unregister_netdevice_many_notify+0x1d5d/0x2330 net/core/dev.c:12008
 unregister_netdevice_many net/core/dev.c:12036 [inline]
 unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:11879
 unregister_netdevice include/linux/netdevice.h:3374 [inline]
 __tun_detach+0xda4/0x1560 drivers/net/tun.c:620
 tun_detach drivers/net/tun.c:636 [inline]
 tun_chr_close+0x10a/0x1c0 drivers/net/tun.c:3390
 __fput+0x449/0xa70 fs/file_table.c:465
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8d6/0x2550 kernel/exit.c:953
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
 get_signal+0x125e/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0x95/0x780 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x8b/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbb27907fc
RSP: 002b:00007ffbb018fec0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: 0000000000000024 RBX: 00007ffbb018ffc0 RCX: 00007ffbb27907fc
RDX: 0000000000000024 RSI: 00007ffbb0190010 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007ffbb018ff14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000005
R13: 00007ffbb018ff68 R14: 00007ffbb0190010 R15: 0000000000000000
 </TASK>
task:syz-executor    state:R  running task     stack:21784 pid:5807  tgid:5807  ppid:5806   task_flags:0x400100 flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7090
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0xd/0x360 kernel/locking/lockdep.c:5826
Code: c3 cc cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 41 54 <53> 48 83 ec 60 4d 89 ce 45 89 c7 41 89 cc 89 54 24 04 89 f3 49 89
RSP: 0018:ffffc900042cf700 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff8215adfc RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8df3dee0
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900042cf858 R11: ffffffff81acdcf0 R12: 1ffff92000859f01
R13: ffffc900042cf840 R14: ffffc900042cf808 R15: ffffffff8171ca05
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1258 [inline]
 __free_frozen_pages+0xb05/0xcd0 mm/page_alloc.c:2721
 discard_slab mm/slub.c:2716 [inline]
 __put_partials+0x161/0x1c0 mm/slub.c:3185
 put_cpu_partial+0x17c/0x250 mm/slub.c:3260
 __slab_free+0x2f7/0x400 mm/slub.c:4512
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_lru_noprof+0x1c6/0x3d0 mm/slub.c:4215
 alloc_inode+0xb8/0x1b0 fs/inode.c:348
 new_inode_pseudo include/linux/fs.h:3309 [inline]
 get_pipe_inode fs/pipe.c:887 [inline]
 create_pipe_files+0x51/0x760 fs/pipe.c:927
 __do_pipe_flags+0x4c/0x2d0 fs/pipe.c:984
 do_pipe2+0x9c/0x170 fs/pipe.c:1035
 __do_sys_pipe2 fs/pipe.c:1053 [inline]
 __se_sys_pipe2 fs/pipe.c:1051 [inline]
 __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:1051
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3dbe18d689
RSP: 002b:00007fffaaff0ee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000125
RAX: ffffffffffffffda RBX: 000055555f7ad5f0 RCX: 00007f3dbe18d689
RDX: 0000000000000007 RSI: 0000000000000000 RDI: 00007fffaaff0f00
RBP: 00007fffaaff12b0 R08: 0000000000000007 R09: 000055555f7aa100
R10: b7e327876ed82641 R11: 0000000000000246 R12: 000055555f7ad480
R13: 000055555f7a82c8 R14: 00007fffaaff1030 R15: 000055555f7b1d78
 </TASK>
rcu: rcu_preempt kthread starved for 8733 jiffies! g100269 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27304 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x168f/0x4c70 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2248
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5870
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 6b 60 d4 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc90000a07858 EFLAGS: 00000206
RAX: 7e41fc8943f64600 RBX: 0000000000000000 RCX: 7e41fc8943f64600
RDX: 0000000000000000 RSI: ffffffff8d924a0f RDI: ffffffff8bc12080
RBP: ffffffff8171ca05 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8171ca05 R12: 0000000000000002
R13: ffffffff8df3dee0 R14: 0000000000000000 R15: 0000000000000246
FS:  0000000000000000(0000) GS:ffff8881261f6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3dbc103d97 CR3: 00000000320ba000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000000c DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4147 [inline]
 slab_alloc_node mm/slub.c:4196 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4203
 skb_ext_maybe_cow net/core/skbuff.c:6969 [inline]
 skb_ext_add+0x1b6/0x8f0 net/core/skbuff.c:7043
 nf_bridge_unshare net/bridge/br_netfilter_hooks.c:169 [inline]
 br_nf_forward_ip+0xc6/0x7e0 net/bridge/br_netfilter_hooks.c:684
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x215/0x3c0 include/linux/netfilter.h:312
 __br_forward+0x41e/0x600 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0xb5/0x160 net/bridge/br_forward.c:190
 br_flood+0x31a/0x6a0 net/bridge/br_forward.c:237
 br_handle_frame_finish+0x146c/0x1950 net/bridge/br_input.c:220
 br_nf_hook_thresh+0x3bf/0x490 net/bridge/br_netfilter_hooks.c:-1
 br_nf_pre_routing_finish_ipv6+0x948/0xd00 net/bridge/br_netfilter_ipv6.c:-1
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x37e/0x6b0 net/bridge/br_netfilter_ipv6.c:184
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:282 [inline]
 br_handle_frame+0x982/0x14c0 net/bridge/br_input.c:433
 __netif_receive_skb_core+0x10de/0x4180 net/core/dev.c:5773
 __netif_receive_skb_one_core net/core/dev.c:5885 [inline]
 __netif_receive_skb+0x72/0x380 net/core/dev.c:6000
 process_backlog+0x60e/0x14f0 net/core/dev.c:6352
 __napi_poll+0xc4/0x480 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0x6ea/0xdf0 net/core/dev.c:7510
 handle_softirqs+0x283/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: 43 d4 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d a3 9f 18 00 f3 0f 1e fa fb f4 <e9> 18 d4 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6
RAX: 7e41fc8943f64600 RBX: ffffffff81977028 RCX: 7e41fc8943f64600
RDX: 0000000000000001 RSI: ffffffff8d73ac7a RDI: ffffffff8bc12080
RBP: ffffc90000197f20 R08: ffff8880b8932b5b R09: 1ffff1101712656b
R10: dffffc0000000000 R11: ffffed101712656c R12: ffffffff8f7e0970
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110038dcb40
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x147
 </TASK>
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/18 10:52 upstream 5723cc3450bc f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in tun_chr_close
2025/08/06 06:52 net ad21f668e8d4 904e669c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in tun_chr_close
* Struck through repros no longer work on HEAD.