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INFO: rcu detected stall in rht_deferred_worker (3)

Status: auto-obsoleted due to no activity on 2026/04/26 08:49
Subsystems: mm
[Documentation on labels]
First crash: 179d, last: 93d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
92f2e53f-1f1f-4ffa-b665-711cbb8ac006 repro INFO: rcu detected stall in rht_deferred_worker (3) 2026/03/08 11:18 2026/03/08 11:18 2026/03/08 11:35 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in rht_deferred_worker (2) mm 1 3 275d 325d 0/29 auto-obsoleted due to no activity on 2025/10/26 04:48
upstream INFO: rcu detected stall in rht_deferred_worker mm 1 1 461d 461d 0/29 auto-obsoleted due to no activity on 2025/04/22 22:56

Sample crash report:
bridge0: received packet on veth0_to_bridge 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): P10328/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=124653, q=585 ncpus=2)
task:kworker/0:12    state:R  running task     stack:22328 pid:10328 tgid:10328 ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: events rht_deferred_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7194
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0xbe1/0x1ea0 arch/x86/kernel/unwind_orc.c:656
Code: 00 00 00 fc ff df 48 c1 e8 03 0f b6 34 10 49 8d 40 01 48 89 c7 48 c1 ef 03 0f b6 14 17 4c 89 c7 83 e7 07 40 38 fe 40 0f 9e c7 <40> 84 f6 40 0f 95 c6 40 84 f7 0f 85 0a 0d 00 00 83 e0 07 38 c2 40
RSP: 0018:ffffc90004c675d8 EFLAGS: 00000246
RAX: ffffffff91637df1 RBX: 0000000000000001 RCX: ffffffff91637dec
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffc90004c67690 R08: ffffffff91637df0 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000017160 R12: ffffc90004c67698
R13: ffffc90004c67648 R14: ffffc90004c679f8 R15: ffffc90004c6767c
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x162/0x1e0 mm/page_owner.c:165
 __reset_page_owner+0x84/0x190 mm/page_owner.c:320
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0x822/0x1130 mm/page_alloc.c:2973
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x127/0x160 mm/slub.c:3886
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 __do_kmalloc_node mm/slub.c:5656 [inline]
 __kvmalloc_node_noprof+0x306/0xac0 mm/slub.c:7140
 bucket_table_alloc.isra.0+0x88/0x460 lib/rhashtable.c:186
 rhashtable_rehash_alloc+0x68/0x110 lib/rhashtable.c:367
 rhashtable_shrink lib/rhashtable.c:411 [inline]
 rht_deferred_worker+0x1876/0x1fd0 lib/rhashtable.c:429
 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: rcu_preempt kthread starved for 240 jiffies! g124653 f0x0 RCU_GP_WAIT_FQS(5) ->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:28408 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5260 [inline]
 __schedule+0xfe4/0x5e10 kernel/sched/core.c:6867
 __schedule_loop kernel/sched/core.c:6949 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:6964
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x21e/0x320 kernel/rcu/tree.c:2285
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 3404 Comm: kworker/R-bat_e Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
Workqueue: bat_events batadv_tt_purge
RIP: 0010:unwind_next_frame+0x4d6/0x1ea0 arch/x86/kernel/unwind_orc.c:520
Code: e8 6f f3 ff ff 48 89 c1 48 85 c0 0f 84 2d 0b 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 79 05 4c 89 fa 48 c1 ea 03 0f b6 04 02 <4c> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 bd 13 00 00 0f b6 41 05
RSP: 0018:ffffc90000006840 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff91f33db4
RDX: 1ffffffff23e67b7 RSI: 0000000000000000 RDI: ffffffff9138b5c8
RBP: ffffc900000068f8 R08: ffffffff91f33dc0 R09: 0000000000000007
R10: 0000000000000200 R11: 00000000000953d1 R12: ffffc90000006900
R13: ffffc900000068b0 R14: ffffc900000068e5 R15: ffffffff91f33db9
FS:  0000000000000000(0000) GS:ffff8881245db000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000002a7030 CR3: 000000000e392000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6674 [inline]
 kmem_cache_free+0x143/0x720 mm/slub.c:6785
 __skb_ext_put+0x102/0x2d0 net/core/skbuff.c:7204
 __skb_ext_del+0xf8/0x360 net/core/skbuff.c:7171
 skb_ext_del include/linux/skbuff.h:5057 [inline]
 nf_bridge_info_free net/bridge/br_netfilter_hooks.c:156 [inline]
 br_nf_dev_queue_xmit+0x7ab/0x2a20 net/bridge/br_netfilter_hooks.c:919
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 br_nf_post_routing+0xcbb/0x16a0 net/bridge/br_netfilter_hooks.c:966
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xbf/0x220 net/netfilter/core.c:623
 nf_hook include/linux/netfilter.h:273 [inline]
 NF_HOOK include/linux/netfilter.h:316 [inline]
 br_forward_finish+0x261/0x4d0 net/bridge/br_forward.c:66
 br_nf_hook_thresh+0x30d/0x420 net/bridge/br_netfilter_hooks.c:1167
 br_nf_forward_finish+0x693/0xb30 net/bridge/br_netfilter_hooks.c:662
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 br_nf_forward_ip.part.0+0x61e/0x820 net/bridge/br_netfilter_hooks.c:716
 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:676 [inline]
 br_nf_forward+0xfe5/0x19f0 net/bridge/br_netfilter_hooks.c:773
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xbf/0x220 net/netfilter/core.c:623
 nf_hook include/linux/netfilter.h:273 [inline]
 NF_HOOK include/linux/netfilter.h:316 [inline]
 __br_forward+0x2f6/0x970 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0xf0/0x180 net/bridge/br_forward.c:191
 br_flood+0x193/0x650 net/bridge/br_forward.c:238
 br_handle_frame_finish+0xf57/0x1f00 net/bridge/br_input.c:229
 br_nf_hook_thresh+0x30d/0x420 net/bridge/br_netfilter_hooks.c:1167
 br_nf_pre_routing_finish_ipv6+0x769/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:318 [inline]
 br_nf_pre_routing_ipv6+0x39c/0x8b0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x93b/0x1510 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:291 [inline]
 br_handle_frame+0xa68/0x1510 net/bridge/br_input.c:442
 __netif_receive_skb_core.constprop.0+0x6d7/0x3460 net/core/dev.c:6039
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6150
 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6265
 process_backlog+0x37a/0x1580 net/core/dev.c:6617
 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0xa40/0xf20 net/core/dev.c:7896
 handle_softirqs+0x1ea/0x910 kernel/softirq.c:622
 do_softirq kernel/softirq.c:523 [inline]
 do_softirq+0xac/0xe0 kernel/softirq.c:510
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_tt_local_purge+0x21c/0x3d0 net/batman-adv/translation-table.c:1315
 batadv_tt_purge+0x8b/0xbd0 net/batman-adv/translation-table.c:3509
 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
 process_scheduled_works kernel/workqueue.c:3340 [inline]
 rescuer_thread+0x8f1/0xf40 kernel/workqueue.c:3528
 kthread+0x3b3/0x730 kernel/kthread.c:463
 ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
net_ratelimit: 13434 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:de:df:69:69:fd:7b, 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: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)
net_ratelimit: 14847 callbacks suppressed
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:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:de:df:69:69:fd:7b, 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:0c, vlan:0)

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/26 08:47 upstream 023777797472 55756628 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in rht_deferred_worker
2025/11/17 17:12 upstream 6a23ae0a96a6 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in rht_deferred_worker
2025/11/01 09:41 linux-next 98bd8b16ae57 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce INFO: rcu detected stall in rht_deferred_worker
* Struck through repros no longer work on HEAD.