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INFO: rcu detected stall in kthread (4)

Status: auto-obsoleted due to no activity on 2025/11/10 02:23
Subsystems: kernel
[Documentation on labels]
First crash: 106d, last: 106d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in kthread mm 1 1 2633d 2633d 0/29 closed as invalid on 2018/09/10 16:00
upstream INFO: rcu detected stall in kthread (3) kernel 1 12 264d 573d 0/29 auto-obsoleted due to no activity on 2025/06/05 06:00
linux-5.15 INFO: rcu detected stall in kthread 1 1 258d 258d 0/3 auto-obsoleted due to no activity on 2025/06/21 04:55
upstream INFO: rcu detected stall in kthread (2) kernel 1 11 2539d 2628d 0/29 closed as dup on 2019/01/02 16:35
linux-4.19 INFO: rcu detected stall in kthread 1 2 1515d 1548d 0/1 auto-closed as invalid on 2022/01/30 14:43

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): P6737/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=13241, q=1351 ncpus=2)
task:syz.2.198       state:R  running task     stack:27656 pid:6737  tgid:6737  ppid:5848   task_flags:0x40044c flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7145
 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 zap_pte_range mm/memory.c:1756 [inline]
 zap_pmd_range mm/memory.c:1818 [inline]
 zap_pud_range mm/memory.c:1847 [inline]
 zap_p4d_range mm/memory.c:1868 [inline]
 unmap_page_range+0xf77/0x42c0 mm/memory.c:1889
 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1932
 unmap_vmas+0x218/0x470 mm/memory.c:1976
 exit_mmap+0x1b9/0xb90 mm/mmap.c:1280
 __mmput+0x12a/0x410 kernel/fork.c:1130
 mmput+0x62/0x70 kernel/fork.c:1152
 exit_mm kernel/exit.c:582 [inline]
 do_exit+0x7c7/0x2bf0 kernel/exit.c:949
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 get_signal+0x2673/0x26d0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9572d8ec23
RSP: 002b:00007ffff681cbc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: 00007f9573b7d000 RBX: 00007f95717f76c0 RCX: 00007f9572d8ec23
RDX: 0000000000000000 RSI: 0000000000021000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000
R10: 0000000000020022 R11: 0000000000000246 R12: 00007ffff681cd20
R13: ffffffffffffffc0 R14: 0000000000001000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 9587 jiffies! g13241 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:I stack:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_gp_fqs_check_wake kernel/rcu/tree.c:2002 [inline]
RIP: 0010:rcu_gp_fqs_loop+0x1b8/0xb00 kernel/rcu/tree.c:2083
Code: 4c 8d ac 24 80 00 00 00 48 c7 84 24 80 00 00 00 00 00 00 00 48 83 e8 58 48 89 84 24 88 00 00 00 48 89 84 24 90 00 00 00 eb 35 <0f> bf 2d 09 25 bb 0c 89 e8 a8 02 75 42 48 8b 05 ac 1f bb 0c 48 85
RSP: 0018:ffffc90000157ca8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff8de4f0f5 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab3597 R11: 0000000000000000 R12: ffffffff8e211200
R13: ffffc90000157d28 R14: 0000000000000000 R15: 0000000000000000
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.17.0-rc1-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:dev_get_by_index_rcu+0x6/0x140 net/core/dev.c:964
Code: 00 b1 b5 f8 e9 02 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 55 <41> 54 41 89 f4 55 53 48 89 fb e8 6b 58 4f f8 48 8d bb 08 03 00 00
RSP: 0018:ffffc90000007688 EFLAGS: 00000246
RAX: 0000000000000007 RBX: ffff888151db3500 RCX: ffffffff8a6ff5d9
RDX: 0000000000000000 RSI: 000000000000001c RDI: ffff8880253a0000
RBP: ffff888151db4e10 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888151db4e10
R13: 0000000000000001 R14: ffff888151db3510 R15: ffffffff8cf70d40
FS:  0000000000000000(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000003b6030 CR3: 0000000030241000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 nf_bridge_get_physindev include/linux/netfilter_bridge.h:63 [inline]
 br_nf_pre_routing_finish_ipv6+0x232/0xfb0 net/bridge/br_netfilter_ipv6.c:108
 NF_HOOK include/linux/netfilter.h:318 [inline]
 br_nf_pre_routing_ipv6+0x3cd/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:158 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0xad5/0x14b0 net/bridge/br_input.c:434
 __netif_receive_skb_core.constprop.0+0xa25/0x48c0 net/core/dev.c:5866
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:5977
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6092
 process_backlog+0x442/0x15e0 net/core/dev.c:6444
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7489
 napi_poll net/core/dev.c:7552 [inline]
 net_rx_action+0xa9f/0xfe0 net/core/dev.c:7679
 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: ac 62 02 c3 cc cc cc cc 0f 1f 00 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 b3 c2 16 00 fb f4 <e9> 4c 0d 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e207e08 EFLAGS: 000002c2
RAX: 0000000000bb4037 RBX: 0000000000000000 RCX: ffffffff8b934c29
RDX: 0000000000000000 RSI: ffffffff8de4f0f5 RDI: ffffffff8c162400
RBP: fffffbfff1c52ef8 R08: 0000000000000001 R09: ffffed1017086655
R10: ffff8880b84332ab R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff8e2977c0 R14: ffffffff90ab3590 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:757
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:330
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
 rest_init+0x16b/0x2b0 init/main.c:744
 start_kernel+0x3ee/0x4d0 init/main.c:1097
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x148
 </TASK>
net_ratelimit: 22116 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:35:67:67:e7:05, 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 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:a2:35:67:67:e7:05, 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)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:a2:35:67:67:e7:05, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 25968 callbacks suppressed
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:a2:35:67:67:e7:05, 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 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:a2:35:67:67:e7:05, 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 veth0_to_bridge with own address as source address (addr:a2:35:67:67:e7:05, vlan:0)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/12 02:19 upstream 8f5ae30d69d7 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in kthread
* Struck through repros no longer work on HEAD.