INFO: rcu detected stall in unwind_get_return_address

Status: auto-obsoleted due to no activity on 2026/04/03 20:45
Reported-by: syzbot+7aac5a3defb57b51d274@syzkaller.appspotmail.com
First crash: 243d, last: 243d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in unwind_get_return_address bpf 1 1 694d 694d 0/29 auto-obsoleted due to no activity on 2024/12/29 10:05
linux-6.1 INFO: rcu detected stall in unwind_get_return_address (2) 1 syz, C 1 1d02h 1d02h 0/3 upstream: reported C repro on 2026/08/24 17:54
linux-6.1 INFO: rcu detected stall in unwind_get_return_address 1 1 186d 186d 0/3 auto-obsoleted due to no activity on 2026/05/31 04:58
linux-5.15 INFO: rcu detected stall in unwind_get_return_address (2) 1 1 22d 22d 0/3 upstream: reported on 2026/08/03 06:35
upstream INFO: rcu detected stall in unwind_get_return_address (2) bpf 1 syz error error 1 256d 252d 0/29 auto-obsoleted due to no activity on 2026/03/22 18:27
upstream INFO: rcu detected stall in unwind_get_return_address (3) prio:low bpf 1 1 93d 93d 0/29 auto-obsoleted due to no activity on 2026/08/22 11:04

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=67f/1/0x4000000000000000 softirq=87162/87163 fqs=5248 
	(detected by 1, t=10502 jiffies, g=123193, q=829)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 29469 Comm: syz.6.6494 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:check_preemption_disabled+0x18/0x110 lib/smp_processor_id.c:14
Code: 00 cc 48 c7 c7 a0 e7 59 8a 48 c7 c6 e0 e7 59 8a eb 00 55 41 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 <65> 8b 05 d9 1d 60 76 65 8b 0d 42 78 60 76 f7 c1 ff ff ff 7f 74 1f
RSP: 0018:ffffc90000006e28 EFLAGS: 00000086
RAX: 8e72a2eef962ff00 RBX: e78ea1eaf2378e33 RCX: 0000000000000001
RDX: 0000000000000002 RSI: ffffffff8a0b2e80 RDI: ffffffff8a59e800
RBP: ffffc90000006f70 R08: dffffc0000000000 R09: fffffbfff1ad26b6
R10: fffffbfff1ad26b6 R11: 1ffffffff1ad26b5 R12: ffff8880518ca900
R13: dffffc0000000000 R14: ffff8880518ca8a0 R15: 1ffff92000000dd8
FS:  0000555594cd0500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc14d043d58 CR3: 0000000050cf1000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff1 DR7: 0000000000000600
Call Trace:
 <IRQ>
 lockdep_recursion_finish kernel/locking/lockdep.c:436 [inline]
 lock_release+0x540/0x870 kernel/locking/lockdep.c:5645
 rcu_read_unlock include/linux/rcupdate.h:773 [inline]
 __perf_event_output kernel/events/core.c:7813 [inline]
 perf_event_output_forward+0x222/0x280 kernel/events/core.c:7822
 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
 perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ed 11 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900000075c0 EFLAGS: 00000206
RAX: 8e72a2eef962ff00 RBX: 1ffff92000000ebc RCX: 8e72a2eef962ff00
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800
RBP: ffffc900000076a0 R08: dffffc0000000000 R09: ffffed1017207662
R10: ffffed1017207662 R11: 1ffff11017207661 R12: ffffffff8c120c00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 is_bpf_text_address+0x24f/0x270 kernel/bpf/core.c:727
 kernel_text_address kernel/extable.c:151 [inline]
 __kernel_text_address+0x9a/0x100 kernel/extable.c:105
 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 rcu_do_batch kernel/rcu/tree.c:2523 [inline]
 rcu_core+0x962/0x15d0 kernel/rcu/tree.c:2763
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:in_lock_functions+0x0/0x20 kernel/locking/spinlock.c:403
Code: cd fe ff ff 48 c7 c1 40 a6 fe 91 80 e1 07 80 c1 03 38 c1 0f 8c 77 ff ff ff 48 c7 c7 40 a6 fe 91 e8 85 0c 5f 00 e9 66 ff ff ff <48> 81 ff 30 4b ab 89 0f 93 c0 48 81 ff be 5a ab 89 0f 92 c1 20 c1
RSP: 0018:ffffc9000309f8e0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffffffff816d0cb7 RCX: ffffffff960b0f03
RDX: ffffc9000309ff00 RSI: ffffffff8a59e7e0 RDI: ffffffff816d0cb7
RBP: 0000000000011601 R08: 0000000000000004 R09: 000000000000000b
R10: fffff52000613f3d R11: 1ffff92000613f3b R12: ffff8880518c9dc0
R13: ffff888061bcec40 R14: 00007f69f90f4749 R15: dffffc0000000000
 get_lock_parent_ip include/linux/ftrace.h:857 [inline]
 preempt_latency_start kernel/sched/core.c:5490 [inline]
 preempt_count_add+0x8d/0x190 kernel/sched/core.c:5515
 is_module_text_address+0x17/0x140 kernel/module.c:4772
 kernel_text_address kernel/extable.c:145 [inline]
 __kernel_text_address+0x84/0x100 kernel/extable.c:105
 unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
 arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 file_free fs/file_table.c:55 [inline]
 __fput+0x627/0x930 fs/file_table.c:324
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f69f90f4749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeacc436e8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000101c27 RCX: 00007f69f90f4749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f69f934cda0 R08: 0000000000000001 R09: 0000001eacc439df
R10: 0000001b30f20000 R11: 0000000000000246 R12: 00007f69f934afac
R13: 00007f69f934afa0 R14: ffffffffffffffff R15: 00007ffeacc43800
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/24 20:44 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in unwind_get_return_address
* Struck through repros no longer work on HEAD.