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INFO: rcu detected stall in tomoyo_write_control (2)

Status: auto-obsoleted due to no activity on 2026/06/17 05:56
Subsystems: tomoyo
Labels: prio:high
[Documentation on labels]
First crash: 101d, last: 94d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
f8edcb95-3f15-4828-9bc8-a429b50f9a25 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ✅ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ✅ VMHostTrigger: ❌ INFO: rcu detected stall in tomoyo_write_control (2) 2026/05/22 06:01 2026/05/22 06:01 2026/05/22 06:59 70ae9b0332c954c7a2e9754a431bc021385efca3

			
		
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in tomoyo_write_control mm 1 1 320d 320d 0/29 auto-obsoleted due to no activity on 2025/11/02 19:09

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): P5928/1:b..l P5921/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=13969, q=2769 ncpus=2)
task:syz.0.5         state:R  running task     stack:26472 pid:5921  tgid:5918  ppid:5826   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline]
RIP: 0010:lock_release kernel/locking/lockdep.c:5885 [inline]
RIP: 0010:lock_release+0x8b/0x320 kernel/locking/lockdep.c:5875
Code: 39 01 00 00 65 4c 8b 25 eb 0c 29 12 41 8b bc 24 54 0b 00 00 85 ff 0f 85 21 01 00 00 48 81 3b 40 47 14 94 0f 84 14 01 00 00 9c <41> 5e fa 48 c7 c7 e7 12 f7 8d e8 b6 21 a9 09 65 ff 05 27 54 29 12
RSP: 0018:ffffc90003f27340 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff8e7e74e0 RCX: ffffffff91870501
RDX: 0000000000000000 RSI: ffffffff8c1b0a20 RDI: 0000000000000000
RBP: ffffffff81b7b2fe R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000001737c R12: ffff888027a1db80
R13: ffffc90003f27400 R14: ffffc90003f27760 R15: ffffc90003f27434
 rcu_lock_release include/linux/rcupdate.h:322 [inline]
 rcu_read_unlock include/linux/rcupdate.h:881 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1193 [inline]
 unwind_next_frame+0x3c3/0x1ea0 arch/x86/kernel/unwind_orc.c:495
 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
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4873
 kmem_alloc_batch+0x49/0x170 lib/debugobjects.c:371
 fill_pool lib/debugobjects.c:420 [inline]
 debug_objects_fill_pool lib/debugobjects.c:742 [inline]
 debug_objects_fill_pool+0x352/0x700 lib/debugobjects.c:714
 debug_object_activate+0x103/0x490 lib/debugobjects.c:831
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common.constprop.0+0x35/0x9b0 kernel/rcu/tree.c:3116
 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_kmalloc+0x8a/0xb0 mm/kasan/common.c:406
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5260 [inline]
 __kmalloc_noprof+0x301/0x850 mm/slub.c:5272
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_encode2+0xfb/0x3c0 security/tomoyo/realpath.c:45
 tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x18c/0x690 security/tomoyo/realpath.c:283
 tomoyo_get_exe+0x63/0xa0 security/tomoyo/util.c:978
 tomoyo_manager security/tomoyo/common.c:954 [inline]
 tomoyo_write_control+0x69e/0x13a0 security/tomoyo/common.c:2864
 vfs_write+0x2aa/0x1070 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8269d9c799
RSP: 002b:00007f826ac7d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f826a016180 RCX: 00007f8269d9c799
RDX: 0000000000008587 RSI: 0000200000000040 RDI: 000000000000000c
RBP: 00007f8269e32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f826a016218 R14: 00007f826a016180 R15: 00007fffe6b3fb78
 </TASK>
task:syz.0.5         state:R  running task     stack:28072 pid:5928  tgid:5918  ppid:5826   task_flags:0x40054c flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline]
RIP: 0010:unwind_next_frame+0xb13/0x1ea0 arch/x86/kernel/unwind_orc.c:600
Code: 3c 02 0f 85 4a f8 ff ff 49 8d 76 f8 ba 08 00 00 00 4d 8d 7d 34 4c 89 ef 48 89 74 24 28 e8 15 f3 ff ff 84 c0 0f 84 39 f8 ff ff <48> 8b 7c 24 28 e8 e3 ec ff ff 48 89 ee 48 8b 4c 24 20 48 ba 00 00
RSP: 0018:ffffc90003f67680 EFLAGS: 00000202
RAX: ffffc90003f68001 RBX: 0000000000000001 RCX: ffffffff9187dca2
RDX: ffffc90003f67901 RSI: ffffc90003f67930 RDI: ffffc90003f67700
RBP: ffffc90003f67738 R08: ffffffff9187dca6 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000017eb2 R12: ffffc90003f67740
R13: ffffc90003f676f0 R14: ffffc90003f67938 R15: ffffc90003f67724
 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+0x7e1/0x10d0 mm/page_alloc.c:2978
 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:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4873
 taskstats_tgid_alloc kernel/taskstats.c:576 [inline]
 taskstats_exit+0x650/0xbd0 kernel/taskstats.c:615
 do_exit+0x659/0x2b60 kernel/exit.c:946
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8269d9c799
RSP: 002b:00007f826ac5c0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f826a016278 RCX: 00007f8269d9c799
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f826a016278
RBP: 00007f826a016270 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f826a016308 R14: 00007fffe6b3fa90 R15: 00007fffe6b3fb78
 </TASK>
rcu: rcu_preempt kthread starved for 235 jiffies! g13969 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:27832 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xdd/0x390 kernel/sched/core.c:7008
 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 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:
CPU: 1 UID: 0 PID: 5934 Comm: kworker/u8:10 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:lock_is_held_type+0xf5/0x140 kernel/locking/lockdep.c:5945
Code: ff ff ff ff 65 0f c1 15 91 48 80 08 83 fa 01 8b 44 24 04 75 2d 9c 5a 80 e6 02 75 47 41 f7 c5 00 02 00 00 74 01 fb 48 83 c4 08 <5b> 5d 41 5c 41 5d 41 5e 41 5f e9 bc 2c 03 00 c3 cc cc cc cc 31 c0
RSP: 0018:ffffc90000a07998 EFLAGS: 00000282
RAX: 0000000000000000 RBX: ffffffff90614468 RCX: 0000000000000001
RDX: 0000000000000046 RSI: ffffffff8de59977 RDI: ffffffff8c1b0aa0
RBP: ffff888027c6db80 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffff
R13: 0000000000000246 R14: ffff888027c6e818 R15: 0000000000000008
FS:  0000000000000000(0000) GS:ffff888124449000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9f5a5b2000 CR3: 000000007c1d4000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 lock_is_held include/linux/lockdep.h:249 [inline]
 lockdep_rtnl_is_held+0x1b/0x40 net/core/rtnetlink.c:182
 __in6_dev_get include/net/addrconf.h:348 [inline]
 ip6_ignore_linkdown include/net/addrconf.h:449 [inline]
 find_match net/ipv6/route.c:780 [inline]
 __find_rr_leaf+0x64b/0x1070 net/ipv6/route.c:868
 find_rr_leaf net/ipv6/route.c:889 [inline]
 rt6_select net/ipv6/route.c:933 [inline]
 fib6_table_lookup+0x50f/0xa10 net/ipv6/route.c:2247
 ip6_pol_route+0x1cc/0x1230 net/ipv6/route.c:2283
 pol_lookup_func include/net/ip6_fib.h:617 [inline]
 fib6_rule_lookup+0x52f/0x720 net/ipv6/fib6_rules.c:120
 ip6_route_input_lookup net/ipv6/route.c:2352 [inline]
 ip6_route_input+0x662/0xc50 net/ipv6/route.c:2655
 ip6_rcv_finish_core.isra.0+0x1a9/0x5a0 net/ipv6/ip6_input.c:66
 ip6_rcv_finish+0x130/0x300 net/ipv6/ip6_input.c:77
 ip_sabotage_in+0x21e/0x290 net/bridge/br_netfilter_hooks.c:990
 nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
 nf_hook_slow+0xbf/0x220 net/netfilter/core.c:623
 nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273
 NF_HOOK include/linux/netfilter.h:316 [inline]
 ipv6_rcv+0xa4/0x3d0 net/ipv6/ip6_input.c:311
 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6164
 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6277
 netif_receive_skb_internal net/core/dev.c:6363 [inline]
 netif_receive_skb+0x139/0x820 net/core/dev.c:6422
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70
 br_handle_frame_finish+0xa74/0x1f60 net/bridge/br_input.c:235
 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+0x90d/0x1550 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+0xcdd/0x1520 net/bridge/br_input.c:442
 __netif_receive_skb_core.constprop.0+0x6c5/0x3550 net/core/dev.c:6051
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6162
 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6277
 process_backlog+0x37a/0x1580 net/core/dev.c:6628
 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7692
 napi_poll net/core/dev.c:7755 [inline]
 net_rx_action+0xa40/0xf20 net/core/dev.c:7912
 handle_softirqs+0x1eb/0x9e0 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:395 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:891 [inline]
 nsim_dev_trap_report_work+0x8c7/0xd10 drivers/net/netdevsim/dev.c:922
 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
 process_scheduled_works kernel/workqueue.c:3359 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
net_ratelimit: 10549 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 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)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/19 05:46 upstream 8a30aeb0d1b4 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in tomoyo_write_control
2026/03/11 11:46 upstream b4f0dd314b39 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in tomoyo_write_control
* Struck through repros no longer work on HEAD.