INFO: rcu detected stall in perf_release

Status: upstream: reported syz repro on 2025/11/02 03:41
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+8ed55d909a092bca9174@syzkaller.appspotmail.com
First crash: 283d, last: 41d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/11/02 linux-5.15.y (ToT) cc5ec8769306 syz [report] INFO: rcu detected stall in corrupted
2025/11/02 upstream (ToT) 691d401c7e0e syz Didn't crash
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in perf_release (2) origin:lts-only 1 syz, C error 2 112d 220d 0/2 upstream: reported C repro on 2026/01/03 14:19
linux-6.1 INFO: rcu detected stall in perf_release 1 2 694d 694d 0/3 auto-obsoleted due to no activity on 2024/12/25 21:00
linux-6.1 INFO: rcu detected stall in perf_release (2) 1 syz, C inconclusive 3 257d 307d 0/3 auto-obsoleted due to no activity on 2026/03/07 13:59
linux-6.6 INFO: rcu detected stall in perf_release 1 syz, C done 1 349d 349d 2/2 fixed on 2025/10/06 10:09
linux-6.1 INFO: rcu detected stall in perf_release (3) 1 syz, C 4 27d 55d 0/3 upstream: reported C repro on 2026/06/17 21:48
upstream INFO: rcu detected stall in perf_release mm cgroups 1 19 2443d 2463d 0/29 auto-closed as invalid on 2020/03/03 09:44
android-5-15 BUG: soft lockup in perf_release (2) 1 1 500d 500d 0/2 auto-obsoleted due to no activity on 2025/06/27 12:18
android-5-15 BUG: soft lockup in perf_release 1 3 781d 844d 0/2 auto-obsoleted due to no activity on 2024/09/19 17:30
▶ ▼ Last patch testing requests (7)
Created Duration User Patch Repo Result
2026/08/08 23:16 20m retest repro linux-5.15.y report log
2026/08/08 23:16 21m retest repro linux-5.15.y report log
2026/08/08 23:16 19m retest repro linux-5.15.y report log
2026/03/23 01:25 13m retest repro linux-5.15.y report log
2026/03/19 15:22 8m retest repro linux-5.15.y error
2026/01/11 16:20 19m retest repro linux-5.15.y report log
2026/01/08 07:53 15m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2026/03/25 22:39 1m fix candidate upstream error job log
2026/02/21 18:18 0m fix candidate upstream error job log
2026/01/22 13:36 1m fix candidate upstream error job log
2025/12/13 13:46 16m fix candidate upstream error job log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=7db/1/0x4000000000000002 softirq=24393/24395 fqs=2 
	(detected by 1, t=10505 jiffies, g=33321, q=557)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8152 Comm: syz.4.3567 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65
Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01
RSP: 0018:ffffc90000006fb8 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 1ffff92000000dfc RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff8880b903b200
RBP: ffffc900000070a0 R08: ffff8880b903b1ff R09: ffff8880b903b1f0
R10: dffffc0000000000 R11: ffffed1017207640 R12: ffff8880b903b208
R13: dffffc0000000000 R14: ffff8880b903b200 R15: 1ffff11017207641
FS:  0000555579bf3500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055557c294a38 CR3: 000000007aa47000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 init_irq_work include/linux/irq_work.h:36 [inline]
 rcu_read_unlock_special+0x32a/0x4a0 kernel/rcu/tree_plugin.h:665
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 __perf_event_output kernel/events/core.c:7813 [inline]
 perf_event_output_forward+0x255/0x2e0 kernel/events/core.c:7822
 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
 perf_swevent_overflow kernel/events/core.c:9591 [inline]
 perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 perf_trace_preemptirq_template+0x2aa/0x360 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+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 f2 cc 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: 2d403fcffe0c8b00 RBX: 1ffff92000000ef4 RCX: 2d403fcffe0c8b00
RDX: dffffc0000000000 RSI: ffffffff8a2b3180 RDI: ffffffff8a7a09c0
RBP: ffffc90000007860 R08: ffffffff901d815f R09: 1ffffffff203b02b
R10: dffffc0000000000 R11: fffffbfff203b02c R12: ffffffff8c323800
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]
 __ip_queue_xmit+0x1242/0x1c00 net/ipv4/ip_output.c:539
 __tcp_transmit_skb+0x1d11/0x3200 net/ipv4/tcp_output.c:1404
 tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314
 tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 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:call_rcu+0x6d6/0x950 kernel/rcu/tree.c:3092
Code: f7 84 24 a0 00 00 00 00 02 00 00 43 c6 44 25 04 f8 75 4f f7 44 24 58 00 02 00 00 74 01 fb 48 c7 84 24 80 00 00 00 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90004e7fbc0 EFLAGS: 00000206
RAX: 2d403fcffe0c8b00 RBX: ffff88807c544c90 RCX: 2d403fcffe0c8b00
RDX: dffffc0000000000 RSI: ffffffff8a2b3180 RDI: ffffffff8a7a09c0
RBP: ffffc90004e7fcf0 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: dffffc0000000000
R13: 1ffff920009cff88 R14: 1ffff11017207654 R15: 000000000000001a
 put_event kernel/events/core.c:5258 [inline]
 perf_event_release_kernel+0x83e/0x8d0 kernel/events/core.c:5383
 perf_release+0x37/0x40 kernel/events/core.c:5393
 __fput+0x234/0x930 fs/file_table.c:311
 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: 0033:0x7f59cccabe59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe2728d238 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffe2728d320 RCX: 00007f59cccabe59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000003a057 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b32420000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f59ccf24fac R14: 00007f59ccf24fa8 R15: 00007f59ccf24fa0
 </TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g33321 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:26736 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 7425 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x843/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:918
Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 f7 bb 4a 00 44 38 e3 75 10 66 90 0f 00 2d b9 cc f3 08 fb f4 <e9> 16 ff ff ff fb e9 10 ff ff ff e8 a7 c0 88 08 89 f9 80 e1 07 38
RSP: 0018:ffffc90000dd08c0 EFLAGS: 00000246
RAX: 0825d233384f9700 RBX: 0000000000000003 RCX: 0825d233384f9700
RDX: dffffc0000000000 RSI: ffffffff8a2b3180 RDI: ffffffff8a7a09c0
RBP: ffffc90000dd0970 R08: ffffffff901d815f R09: 1ffffffff203b02b
R10: dffffc0000000000 R11: fffffbfff203b02c R12: 0000000000000003
R13: ffff8880b913b154 R14: dffffc0000000000 R15: 1ffff920001ba118
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115
 spin_lock include/linux/spinlock.h:364 [inline]
 tcp_write_timer+0x29/0x280 net/ipv4/tcp_timer.c:673
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 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:unwind_next_frame+0x3/0x1d90 arch/x86/kernel/unwind_orc.c:423
Code: 5b 41 5e 41 5f c3 89 d9 80 e1 07 80 c1 03 38 c1 7c 97 48 89 df e8 7d 34 89 00 eb 8d 66 2e 0f 1f 84 00 00 00 00 00 90 55 41 57 <41> 56 41 55 41 54 53 48 81 ec 88 00 00 00 48 89 fb 49 be 00 00 00
RSP: 0018:ffffc90004e3f970 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc90004e3fa40 RCX: 0000000080000001
RDX: dffffc0000000000 RSI: ffffffff8876da18 RDI: ffffc90004e3f988
RBP: ffffc90004e3fa10 R08: ffffc90004e3fa50 R09: 0000000000000005
R10: dffffc0000000000 R11: fffff520009c7f3d R12: ffff88802078d940
R13: dffffc0000000000 R14: ffffffff8167c1b0 R15: ffffc90004e3f988
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 apparmor_sk_alloc_security+0x74/0x100 security/apparmor/lsm.c:785
 security_sk_alloc+0x6a/0xa0 security/security.c:2309
 sk_prot_alloc+0x101/0x210 net/core/sock.c:1869
 sk_alloc+0x2f/0x310 net/core/sock.c:1922
 inet_create+0x728/0xef0 net/ipv4/af_inet.c:322
 __sock_create+0x47b/0x900 net/socket.c:1495
 sock_create net/socket.c:1551 [inline]
 __sys_socket+0xe2/0x170 net/socket.c:1593
 __do_sys_socket net/socket.c:1602 [inline]
 __se_sys_socket net/socket.c:1600 [inline]
 __x64_sys_socket+0x76/0x80 net/socket.c:1600
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f243d88d6c7
Code: f0 ff ff 77 06 c3 0f 1f 44 00 00 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc6365a418 EFLAGS: 00000202 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 00007f243dad6460 RCX: 00007f243d88d6c7
RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002
RBP: 00007ffc6365ab3c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000051
R13: 00000000000927c0 R14: 0000000000000000 R15: 00007ffc6365ab90
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/08 11:06 linux-5.15.y dc027a595035 cc095639 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in perf_release
2025/12/24 17:25 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in perf_release
2025/11/02 03:40 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in perf_release
2026/07/01 20:56 linux-5.15.y eceeec79dbc6 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in perf_release
2026/02/12 23:30 linux-5.15.y e45d5d41c134 504cb1bf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in perf_release
* Struck through repros no longer work on HEAD.