syzbot


INFO: rcu detected stall in kthread (3)

Status: auto-obsoleted due to no activity on 2025/06/05 06:00
Subsystems: kernel
[Documentation on labels]
First crash: 449d, last: 140d
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in kthread mm 1 1 2510d 2510d 0/29 closed as invalid on 2018/09/10 16:00
linux-5.15 INFO: rcu detected stall in kthread 1 1 134d 134d 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 2416d 2505d 0/29 closed as dup on 2019/01/02 16:35
linux-4.19 INFO: rcu detected stall in kthread 1 2 1392d 1424d 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)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ca:c4:77:3a:92:c3, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10937/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=126801, q=305 ncpus=2)
task:kworker/u8:25   state:R  running task     stack:21104 pid:10937 tgid:10937 ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue:  0x0 (events_unbound)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6944
 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6968
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12
 unwind_next_frame+0x18f8/0x22d0 arch/x86/kernel/unwind_orc.c:672
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x430 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_frozen_pages+0xe0d/0x10e0 mm/page_alloc.c:2660
 discard_slab mm/slub.c:2684 [inline]
 __put_partials+0x160/0x1c0 mm/slub.c:3153
 put_cpu_partial+0x17c/0x250 mm/slub.c:3228
 __slab_free+0x290/0x380 mm/slub.c:4479
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 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]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_node_track_caller_noprof+0x237/0x4c0 mm/slub.c:4313
 kvasprintf+0xdf/0x190 lib/kasprintf.c:25
 __kthread_create_on_node+0x1a9/0x3c0 kernel/kthread.c:520
 kthread_create_on_node+0xde/0x130 kernel/kthread.c:588
 create_worker+0x2a1/0x720 kernel/workqueue.c:2802
 maybe_create_worker kernel/workqueue.c:3063 [inline]
 manage_workers kernel/workqueue.c:3115 [inline]
 worker_thread+0x318/0xd30 kernel/workqueue.c:3375
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: rcu_preempt kthread starved for 10370 jiffies! g126801 f0x0 RCU_GP_DOING_FQS(6) ->state=0x0 ->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:R  running task     stack:26104 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7087
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__might_resched+0x4/0x780 kernel/sched/core.c:8722
Code: 8c 70 ff ff ff 48 89 df e8 19 e6 97 00 e9 63 ff ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec e0 00
RSP: 0018:ffffc90000167bf8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88801da804a9 RCX: ffffffff81a8be10
RDX: 0000000000000000 RSI: 0000000000000a73 RDI: ffffffff8c2bfdc1
RBP: ffffc90000167d50 R08: ffffffff903cf477 R09: 1ffffffff2079e8e
R10: dffffc0000000000 R11: fffffbfff2079e8f R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff88801da80000 R15: ffffffff8eb3e040
 force_qs_rnp kernel/rcu/tree.c:2675 [inline]
 rcu_gp_fqs_loop+0x742/0x1330 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </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 6.14.0-rc5-syzkaller-00105-gf315296c92fd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:unwind_next_frame+0x60a/0x22d0 arch/x86/kernel/unwind_orc.c:517
Code: 84 73 0b 00 00 48 83 c3 10 e9 06 02 00 00 83 fb 04 0f 84 0e 02 00 00 83 fb 05 0f 85 e6 09 00 00 48 8b 44 24 58 42 80 3c 20 00 <74> 0d 4c 89 f7 e8 6c df bb 00 48 8b 54 24 10 49 8b 06 48 89 04 24
RSP: 0018:ffffc900000060f0 EFLAGS: 00000246
RAX: 1ffff92000000c3f RBX: 0000000000000005 RCX: ffffffff90a91574
RDX: ffffffff914ca1e2 RSI: ffffffff914ca1e2 RDI: 0000000000000001
RBP: ffffc90000006210 R08: 0000000000000001 R09: ffffc900000062b0
R10: ffffc90000006210 R11: ffffffff81ad5ae0 R12: dffffc0000000000
R13: ffffc900000061c0 R14: ffffc900000061f8 R15: ffffffff914ca1e6
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd5b1432c8e CR3: 0000000033054000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000097 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2353 [inline]
 slab_free mm/slub.c:4609 [inline]
 kmem_cache_free+0x195/0x410 mm/slub.c:4711
 br_nf_dev_queue_xmit+0x4c8/0x2550
 NF_HOOK+0x700/0x7c0 include/linux/netfilter.h:314
 br_nf_post_routing+0xa20/0xe80 net/bridge/br_netfilter_hooks.c:969
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x2a7/0x460 include/linux/netfilter.h:312
 br_forward_finish+0xd8/0x130 net/bridge/br_forward.c:66
 br_nf_forward_finish+0xb49/0xfb0 net/bridge/br_netfilter_hooks.c:665
 NF_HOOK+0x700/0x7c0 include/linux/netfilter.h:314
 br_nf_forward_ip+0x61e/0x7b0 net/bridge/br_netfilter_hooks.c:719
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc3/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x2a7/0x460 include/linux/netfilter.h:312
 __br_forward+0x489/0x660 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0xb3/0x150 net/bridge/br_forward.c:190
 br_flood+0x2e4/0x680 net/bridge/br_forward.c:237
 br_handle_frame_finish+0x18d2/0x2000 net/bridge/br_input.c:220
 br_nf_hook_thresh+0x472/0x590
 br_nf_pre_routing_finish_ipv6+0xaa0/0xdd0
 NF_HOOK include/linux/netfilter.h:314 [inline]
 br_nf_pre_routing_ipv6+0x379/0x770 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+0x9f3/0x1530 net/bridge/br_input.c:433
 __netif_receive_skb_core+0x13e7/0x4540 net/core/dev.c:5787
 __netif_receive_skb_one_core net/core/dev.c:5891 [inline]
 __netif_receive_skb+0x12f/0x650 net/core/dev.c:6006
 process_backlog+0x662/0x15b0 net/core/dev.c:6354
 __napi_poll+0xcb/0x490 net/core/dev.c:7188
 napi_poll net/core/dev.c:7257 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:7379
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 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:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 80 d6 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d 05 d0 81 00 f3 0f 1e fa fb f4 <fa> c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffffff8e807ca8 EFLAGS: 00000246
RAX: ffffffff8e896580 RBX: ffff88801dea6864 RCX: 00000000003b21d1
RDX: 0000000000000001 RSI: ffff88801dea6800 RDI: ffff88801dea6864
RBP: 000000000003aab8 R08: ffff8880b863799b R09: 1ffff110170c6f33
R10: dffffc0000000000 R11: ffffffff8c08c010 R12: ffff888020fe0800
R13: 0000000000000001 R14: 0000000000000001 R15: ffffffff8f338260
 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:699
 cpuidle_enter_state+0x109/0x470 drivers/cpuidle/cpuidle.c:268
 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:389
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:230 [inline]
 do_idle+0x372/0x5c0 kernel/sched/idle.c:325
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
 rest_init+0x2dc/0x300 init/main.c:743
 start_kernel+0x484/0x510 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:515
 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:496
 common_startup_64+0x13e/0x147
 </TASK>
net_ratelimit: 20698 callbacks suppressed
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ca:c4:77:3a:92:c3, vlan:0)
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
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 veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
net_ratelimit: 22371 callbacks suppressed
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)
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
bridge0: received packet on veth0_to_bridge with own address as source address (addr:ca:c4:77:3a:92:c3, vlan:0)
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
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)

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/07 05:57 upstream f315296c92fd 831e3629 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in kthread
2024/12/30 09:14 upstream 4099a71718b0 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in kthread
2024/12/16 06:38 upstream dccbe2047a5b 7cbfbb3a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in kthread
2024/05/01 21:04 upstream 18daea77cca6 3ba885bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 INFO: rcu detected stall in kthread
2025/01/02 03:41 net 4f619d518db9 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in kthread
2024/11/01 21:59 net 0144c06c5890 f00eed24 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in kthread
2024/10/13 15:28 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d73dc7b182be 084d8178 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in kthread
2024/08/03 01:30 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing d483f034f032 1786a2a8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in kthread
2024/07/21 09:04 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 3c3ff7be9729 b88348e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in kthread
2024/07/12 15:54 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing b72749301112 eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in kthread
2024/07/05 21:00 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 179264157bba 2a40360c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in kthread
2024/06/11 10:47 linux-next a957267fa7e9 c7d7d815 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in kthread
* Struck through repros no longer work on HEAD.