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INFO: rcu detected stall in tty_release (4)

Status: auto-obsoleted due to no activity on 2026/06/30 05:25
Subsystems: serial
Labels: prio:normal
[Documentation on labels]
First crash: 96d, last: 96d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
4056c36f-4f97-465c-b315-ebc3f7fc77aa assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ INFO: rcu detected stall in tty_release (4) 2026/05/26 03:38 2026/05/26 03:38 2026/05/26 04:32 c69befb30ac10e158cc9d1557b508ee3f0eca1de

			
		
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in tty_release (2) mm 1 4 516d 607d 0/29 auto-obsoleted due to no activity on 2025/05/06 09:10
upstream INFO: rcu detected stall in tty_release (3) net bluetooth 1 2 318d 373d 0/29 auto-obsoleted due to no activity on 2025/11/19 23:52
upstream INFO: rcu detected stall in tty_release serial 1 3 719d 787d 0/29 auto-obsoleted due to no activity on 2024/10/15 04:06

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)
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): P11177/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=49381, q=1605 ncpus=1)
task:syz.4.1070      state:R  running task     stack:26824 pid:11177 tgid:11173 ppid:8706   task_flags:0x40054c flags:0x00080001
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:lock_release+0x19e/0x320 kernel/locking/lockdep.c:5893
Code: ff 65 0f c1 05 8b 9e 29 12 83 f8 01 0f 85 3d 01 00 00 9c 58 f6 c4 02 0f 85 28 01 00 00 41 f7 c6 00 02 00 00 0f 85 de 00 00 00 <48> 8b 44 24 10 65 48 2b 05 dd 56 29 12 0f 85 63 01 00 00 48 83 c4
RSP: 0018:ffffc90005a77198 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e7e7760 RCX: ffffc90005a771a4
RDX: 0000000000000003 RSI: ffffffff8de5c538 RDI: ffffffff8c1b1920
RBP: ffffffff81b7c2fe R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000000aa16 R12: ffff88801e789e80
R13: ffffc90005a77250 R14: 0000000000000202 R15: 0000000000000004
 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_assert_init+0x101/0x300 lib/debugobjects.c:1020
 debug_timer_assert_init kernel/time/timer.c:803 [inline]
 debug_assert_init kernel/time/timer.c:848 [inline]
 __try_to_del_timer_sync+0x76/0x160 kernel/time/timer.c:1457
 __timer_delete_sync+0xf7/0x1c0 kernel/time/timer.c:1621
 univ8250_release_irq+0x21/0x2d0 drivers/tty/serial/8250/8250_core.c:303
 serial8250_shutdown+0x5e/0x80 drivers/tty/serial/8250/8250_port.c:2420
 uart_port_shutdown+0xf7/0x1a0 drivers/tty/serial/serial_core.c:1862
 uart_tty_port_shutdown+0x231/0x6c0 drivers/tty/serial/serial_core.c:1737
 tty_port_shutdown+0x21e/0x270 drivers/tty/tty_port.c:351
 tty_port_close drivers/tty/tty_port.c:684 [inline]
 tty_port_close+0x57/0x1a0 drivers/tty/tty_port.c:679
 uart_close+0x7d/0x270 drivers/tty/serial/serial_core.c:1718
 tty_release+0x40e/0x1300 drivers/tty/tty_io.c:1745
 __fput+0x3ff/0xb40 fs/file_table.c:469
 task_work_run+0x150/0x240 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x8b8/0x2b60 kernel/exit.c:976
 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: 0033:0x7f71ea19c799
RSP: 002b:00007f71eb003028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: 000000000002ec41 RBX: 00007f71ea416090 RCX: 00007f71ea19c799
RDX: 00000000fffffe82 RSI: 0000200000000040 RDI: 0000000000000003
RBP: 00007f71ea232c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f71ea416128 R14: 00007f71ea416090 R15: 00007ffe24a80bf8
 </TASK>
rcu: rcu_preempt kthread starved for 258 jiffies! g49381 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: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: 0 UID: 0 PID: 6744 Comm: kworker/u8:19 Tainted: G     U       L      syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER, [L]=SOFTLOCKUP
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_acquire+0x5e/0x380 kernel/locking/lockdep.c:5872
Code: 05 fb 5d 29 12 83 f8 07 0f 87 f0 00 00 00 48 0f a3 05 c6 7f f5 0e 0f 82 c2 02 00 00 8b 35 8e b3 f5 0e 85 f6 0f 85 dd 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 5d 29 12 0f 85 02 03 00 00 48 83 c4
RSP: 0018:ffffc90000006648 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000008
RDX: 0000000000000000 RSI: ffffffff8de5c538 RDI: ffffffff8c1b1920
RBP: ffffffff8e7e7760 R08: 0000000012749f35 R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124343000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000090000 CR3: 0000000076796000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock include/linux/rcupdate.h:850 [inline]
 batadv_tt_hash_find+0x1a0/0x6e0 net/batman-adv/translation-table.c:143
 batadv_tt_local_hash_find net/batman-adv/translation-table.c:178 [inline]
 batadv_tt_local_add+0x11d/0x1f90 net/batman-adv/translation-table.c:613
 batadv_interface_tx+0x5aa/0x1c10 net/batman-adv/mesh-interface.c:236
 __netdev_start_xmit include/linux/netdevice.h:5325 [inline]
 netdev_start_xmit include/linux/netdevice.h:5334 [inline]
 xmit_one net/core/dev.c:3883 [inline]
 dev_hard_start_xmit+0x121/0x7d0 net/core/dev.c:3899
 __dev_queue_xmit+0x32c1/0x4800 net/core/dev.c:4849
 dev_queue_xmit include/linux/netdevice.h:3385 [inline]
 br_dev_queue_push_xmit+0x360/0x550 net/bridge/br_forward.c:53
 br_nf_dev_queue_xmit+0x741/0x2a20 net/bridge/br_netfilter_hooks.c:920
 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+0xff4/0x1f60 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+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:6063
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6174
 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6289
 process_backlog+0x37a/0x1580 net/core/dev.c:6640
 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7704
 napi_poll net/core/dev.c:7767 [inline]
 net_rx_action+0xa40/0xf20 net/core/dev.c:7924
 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: 7695 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)
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)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
net_ratelimit: 11863 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 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)
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)
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)

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/01 05:16 upstream d0c3bcd5b897 ef441708 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in tty_release
* Struck through repros no longer work on HEAD.