INFO: rcu detected stall in free_obj_work (2)

Status: auto-obsoleted due to no activity on 2026/01/30 19:31
Subsystems: kernel
[Documentation on labels]
First crash: 517d, last: 335d
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in free_obj_work 1 1 28d 28d 0/3 upstream: reported on 2026/09/05 04:12
upstream INFO: rcu detected stall in free_obj_work net virt 1 2 804d 815d 0/29 auto-obsoleted due to no activity on 2024/10/18 07:59

Sample crash report:
sched: DL replenish lagged too much
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5811/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=17229, q=828466 ncpus=2)
task:kworker/0:3     state:R  running task     stack:22584 pid:5811  tgid:5811  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events free_obj_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6929
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
 irqentry_exit+0x36/0x90 kernel/entry/common.c:211
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872
Code: 57 0b 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 a2 14 ea 0e 0f 82 74 02 00 00 8b 35 1a 45 ea 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 b9 56 0b 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc90003057678 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c4460 RCX: 00000000abec5626
RDX: 0000000000000000 RSI: ffffffff8dadd953 RDI: ffffffff8bf1e3c0
RBP: 0000000000000002 R08: 33dbd28ae98a6442 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
 kasan_save_free_info mm/kasan/kasan.h:406 [inline]
 poison_slab_object mm/kasan/common.c:252 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2523 [inline]
 slab_free mm/slub.c:6611 [inline]
 kmem_cache_free+0x2d4/0x6c0 mm/slub.c:6721
 free_object_list.isra.0+0xf8/0x2a0 lib/debugobjects.c:326
 free_obj_work+0x19f/0x3d0 lib/debugobjects.c:513
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread starved for 1921 jiffies! g17229 f0x2 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:28232 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7026
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:__in6_dev_get include/net/addrconf.h:347 [inline]
RIP: 0010:ip6_rcv_core+0xce7/0x1c30 net/ipv6/ip6_input.c:164
Code: ff ff e8 1c 90 b1 f7 e8 d7 1e 34 ff 31 ff 89 c5 89 c6 e8 ec 8a b1 f7 40 84 ed 0f 85 34 f4 ff ff e8 fe 8f b1 f7 e8 b9 71 95 f7 <31> ff 89 c5 89 c6 e8 2e 8b b1 f7 85 ed 0f 85 17 f4 ff ff e8 e1 8f
RSP: 0018:ffffc90000a08b20 EFLAGS: 00000286
RAX: 0000000000000001 RBX: ffff888196f30c80 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8dadd953 RDI: ffffffff8bf1e3c0
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff8880792af000
R13: ffff888023790000 R14: ffff88807bd4c000 R15: ffff88807bd4c000
FS:  0000000000000000(0000) GS:ffff888124ad9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558d4665c8 CR3: 000000005c0f9000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 ipv6_rcv+0x7b/0x650 net/ipv6/ip6_input.c:308
 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6079
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6192
 process_backlog+0x439/0x15e0 net/core/dev.c:6544
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0x97f/0xef0 net/core/dev.c:7784
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: f7 74 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 43 05 24 00 fb f4 <e9> 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6
RAX: 00000000021b9567 RBX: 0000000000000001 RCX: ffffffff8b6622a9
RDX: 0000000000000000 RSI: ffffffff8db0330f RDI: ffffffff8bf1e3c0
RBP: ffffed1003b53490 R08: 0000000000000001 R09: ffffed10170a6655
R10: ffff8880b85332ab R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801da9a480 R14: ffffffff90832dd0 R15: 0000000000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:190 [inline]
 do_idle+0x38d/0x500 kernel/sched/idle.c:330
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/16 01:55 upstream 1f4a222b0e33 19568248 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in free_obj_work
2025/08/28 10:29 upstream 07d9df80082b 443c11c7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in free_obj_work
2025/08/08 23:32 upstream 37816488247d 987b750d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in free_obj_work
2025/07/20 02:25 upstream f4a40a4282f4 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in free_obj_work
2025/05/26 20:33 upstream 0ff41df1cb26 874a1386 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in free_obj_work
2025/11/01 19:27 linux-next 98bd8b16ae57 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in free_obj_work
2025/05/03 21:09 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 588d032e9e56 b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in free_obj_work
* Struck through repros no longer work on HEAD.