INFO: rcu detected stall in perf_release (2)

Status: upstream: reported C repro on 2026/01/03 14:19
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+efff49bb0ee448d970de@syzkaller.appspotmail.com
First crash: 227d, last: 119d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/01/03 linux-6.6.y (ToT) 5fa4793a2d2d C [report] INFO: rcu detected stall in smp_call_function
2026/01/03 upstream (ToT) aacb0a6d604a C Didn't crash
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in perf_release origin:lts-only 1 syz error 5 47d 289d 0/3 upstream: reported syz repro on 2025/11/02 03:41
linux-6.1 INFO: rcu detected stall in perf_release 1 2 700d 700d 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 264d 313d 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 355d 355d 2/2 fixed on 2025/10/06 10:09
linux-6.1 INFO: rcu detected stall in perf_release (3) origin:lts-only 1 syz, C 5 4d22h 61d 0/3 upstream: reported C repro on 2026/06/17 21:48
upstream INFO: rcu detected stall in perf_release mm cgroups 1 19 2449d 2469d 0/29 auto-closed as invalid on 2020/03/03 09:44
android-5-15 BUG: soft lockup in perf_release (2) 1 1 507d 507d 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 787d 850d 0/2 auto-obsoleted due to no activity on 2024/09/19 17:30
▶ ▼ Fix bisection attempts (5)
Created Duration User Patch Repo Result
2026/05/29 06:07 56m fix candidate upstream error job log
2026/04/28 06:09 25m fix candidate upstream error job log
2026/03/25 13:55 1m fix candidate upstream error job log
2026/02/23 04:17 1m fix candidate upstream error job log
2026/01/23 13:09 1m fix candidate upstream error job log

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10102 ticks this GP) idle=504c/1/0x4000000000000000 softirq=13011/13018 fqs=5025
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1453232         12            0
rcu: 	cputime:    16081      36408           43   ==> 52510(ms)
rcu: 	(t=10503 jiffies g=11433 q=1152 ncpus=2)
CPU: 1 PID: 5927 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:unwind_next_frame+0x642/0x2970 arch/x86/kernel/unwind_orc.c:505
Code: 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 d0 1c 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 dc 1c 00 00 45 0f b6 76 01 <41> 83 e6 07 4c 89 f7 48 c7 c6 c0 07 fa 8c e8 ab e8 4b 00 4d 85 f6
RSP: 0018:ffffc900001ef878 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8f19e560 RCX: ffff88807b771e00
RDX: 0000000000000100 RSI: ffffffff81df530d RDI: ffffffff81df5300
RBP: ffffc900001ef998 R08: ffffc900001efa10 R09: 0000000000000001
R10: 0000000000000004 R11: 0000000000000100 R12: ffffc900001ef948
R13: dffffc0000000000 R14: 0000000000000002 R15: ffffffff8f19e565
FS:  000055558d679500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000001df50 CR3: 0000000075d0b000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x270 mm/slub.c:3852
 packet_rcv+0x16b/0x13d0 net/packet/af_packet.c:2278
 dev_queue_xmit_nit+0xb16/0xbb0 net/core/dev.c:2385
 xmit_one net/core/dev.c:3640 [inline]
 dev_hard_start_xmit+0x148/0x740 net/core/dev.c:3660
 sch_direct_xmit+0x25e/0x4c0 net/sched/sch_generic.c:345
 __dev_xmit_skb net/core/dev.c:3881 [inline]
 __dev_queue_xmit+0x165d/0x3660 net/core/dev.c:4416
 NF_HOOK+0x331/0x3b0 include/linux/netfilter.h:-1
 arp_xmit+0x16c/0x270 net/ipv4/arp.c:664
 arp_process+0x13ba/0x17b0 net/ipv4/arp.c:854
 NF_HOOK+0x331/0x3b0 include/linux/netfilter.h:-1
 __netif_receive_skb_list_ptype net/core/dev.c:5694 [inline]
 __netif_receive_skb_list_core+0x6ea/0x750 net/core/dev.c:5737
 __netif_receive_skb_list net/core/dev.c:5789 [inline]
 netif_receive_skb_list_internal+0x943/0xca0 net/core/dev.c:5880
 gro_normal_list include/net/gro.h:451 [inline]
 gro_normal_one include/net/gro.h:464 [inline]
 napi_skb_finish net/core/gro.c:575 [inline]
 napi_gro_receive+0x565/0xb00 net/core/gro.c:605
 receive_buf+0x2203/0x3820 drivers/net/virtio_net.c:1870
 virtnet_receive drivers/net/virtio_net.c:2155 [inline]
 virtnet_poll+0x5dd/0x1280 drivers/net/virtio_net.c:2229
 __napi_poll+0xc0/0x460 net/core/dev.c:6650
 napi_poll net/core/dev.c:6717 [inline]
 net_rx_action+0x616/0xc40 net/core/dev.c:6853
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5255
Code: 0f 84 33 01 00 00 48 85 db 0f 85 52 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 00 89 32 09 e8 9b 29 30 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc90003337858 EFLAGS: 00000282
RAX: c9fdcf51b03a4d00 RBX: 0000000000000000 RCX: c9fdcf51b03a4d00
RDX: dffffc0000000000 RSI: ffffffff8acac9e0 RDI: ffffffff8b1c8e60
RBP: ffffc900033378b0 R08: ffffffff8e8b15ef R09: 1ffffffff1d162bd
R10: dffffc0000000000 R11: fffffbfff1d162be R12: ffff88807b771e00
R13: dffffc0000000000 R14: ffff88802129da00 R15: ffff8880b8f3cac8
 context_switch kernel/sched/core.c:5384 [inline]
 __schedule+0x155b/0x45a0 kernel/sched/core.c:6700
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:perf_remove_from_owner+0x0/0x4f0 kernel/events/core.c:5326
Code: 0b e9 54 ff ff ff e8 0f 94 d8 08 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c aa f8 ff ff 48 89 df e8 87 a3 31 00 e9 9d f8 ff ff 66 90 <55> 41 57 41 56 41 55 41 54 53 48 83 ec 28 48 89 fd e8 fa 6b d9 ff
RSP: 0018:ffffc90003337c58 EFLAGS: 00000293
RAX: ffffffff81adae53 RBX: ffff88802bfc8618 RCX: ffff88807b771e00
RDX: 0000000000000000 RSI: ffff888026c56280 RDI: ffff88802bfc8618
RBP: ffffc90003337d40 R08: ffff88801b686787 R09: 1ffff110036d0cf0
R10: dffffc0000000000 R11: ffffed10036d0cf1 R12: 1ffff11004d8ac83
R13: ffffffff81b1b790 R14: ffffc90003337cc0 R15: ffff888148c4b7b0
 perf_event_release_kernel+0x140/0x8d0 kernel/events/core.c:5403
 perf_release+0x3b/0x40 kernel/events/core.c:5513
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe579f9c819
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:00007ffce31ad288 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffce31ad370 RCX: 00007fe579f9c819
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001df50 R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33f20000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe57a215fac R14: 00007fe57a215fa8 R15: 00007fe57a215fa0
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/04/21 12:47 linux-6.6.y 9760bf04666d 3f2e655b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in perf_release
2026/01/03 14:19 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in perf_release
* Struck through repros no longer work on HEAD.