syzbot


INFO: rcu detected stall in sys_close (2)

Status: upstream: reported on 2026/06/20 04:40
Reported-by: syzbot+8d76ca4f73bf1c160804@syzkaller.appspotmail.com
First crash: 18d, last: 18d
Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_close (3) kernel 1 1 1412d 1412d 0/29 auto-obsoleted due to no activity on 2022/10/25 14:50
linux-5.15 INFO: rcu detected stall in sys_close (2) 1 1 233d 233d 0/3 auto-obsoleted due to no activity on 2026/02/25 04:01
upstream INFO: rcu detected stall in sys_close (4) fs 1 1 1335d 1335d 0/29 auto-obsoleted due to no activity on 2023/02/13 19:04
linux-5.15 INFO: rcu detected stall in sys_close 1 1 801d 801d 0/3 auto-obsoleted due to no activity on 2024/08/05 21:33
linux-6.6 INFO: rcu detected stall in close origin:lts-only 1 C error 2 190d 210d 0/2 upstream: reported C repro on 2025/12/10 03:57
upstream INFO: rcu detected stall in sys_close (7) prio:high fs 1 C error 21 13d 810d 0/29 upstream: reported C repro on 2024/04/19 01:14
linux-6.1 INFO: rcu detected stall in sys_close origin:lts-only 1 C done 1 215d 247d 3/3 fixed on 2026/01/11 15:32
upstream INFO: rcu detected stall in sys_close fs 1 1 1650d 1650d 0/29 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in sys_close (6) fs 1 3 909d 990d 0/29 auto-obsoleted due to no activity on 2024/04/10 05:01
upstream INFO: rcu detected stall in sys_close (2) fs 1 3 1507d 1557d 0/29 auto-closed as invalid on 2022/08/21 03:13
upstream INFO: rcu detected stall in sys_close (5) net 1 C done 1 1044d 1044d 23/29 fixed on 2023/10/12 12:48

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2685 jiffies s: 26785 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 11646 Comm: syz.0.2206 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__perf_event_output kernel/events/core.c:7732 [inline]
RIP: 0010:perf_event_output_forward+0x19f/0x2f0 kernel/events/core.c:7750
Code: ba 38 00 00 00 4c 89 f7 31 f6 e8 2c 8c 2e 00 4c 89 ef 4c 89 e6 4c 89 fa 48 8b 4c 24 10 e8 19 da ff ff 0f b7 8c 24 a6 00 00 00 <4c> 89 f7 4c 89 e6 4c 89 fa e8 e3 c3 03 00 4d 89 fd 4d 89 f7 41 89
RSP: 0018:ffffc900000073e0 EFLAGS: 00000046
RAX: d8f99cd1f73b5800 RBX: 1ffff92000000e80 RCX: 0000000000000128
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900000074f0 R08: ffffffff8e200f6f R09: 1ffffffff1c401ed
R10: dffffc0000000000 R11: fffffbfff1c401ee R12: ffffc900000076c0
R13: ffffc90000007480 R14: ffffc90000007420 R15: ffff888086ad7200
FS:  00007f6f2ba6e6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000100000000 CR3: 0000000075b3d000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __perf_event_overflow+0x457/0x630 kernel/events/core.c:9496
 perf_swevent_overflow kernel/events/core.c:9579 [inline]
 perf_swevent_event+0x315/0x570 kernel/events/core.c:9630
 perf_tp_event+0x36b/0xc10 kernel/events/core.c:10064
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10032
 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x7f/0x510 kernel/rcu/tree_plugin.h:685
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 e2 82 95 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007ae0 EFLAGS: 00000206
RAX: d8f99cd1f73b5800 RBX: 1ffff92000000f64 RCX: d8f99cd1f73b5800
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adee1a0
RBP: ffffc90000007bd0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01
R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8e3bb00 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ieee80211_iterate_active_interfaces_atomic+0x156/0x170 net/mac80211/util.c:826
 mac80211_hwsim_beacon+0xb7/0x1b0 drivers/net/wireless/mac80211_hwsim.c:2147
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_run_softirq+0x173/0x290 kernel/time/hrtimer.c:1832
 handle_softirqs+0x291/0x910 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:preempt_count_sub+0xed/0x160 kernel/sched/core.c:5738
Code: 85 c7 0c 00 75 98 48 c7 c7 60 a7 8b 8a 48 c7 c6 40 a8 8b 8a e8 74 f9 f4 ff 0f 0b eb 81 48 c7 c1 40 91 bf 96 80 e1 07 80 c1 03 <38> c1 0f 8c 2e ff ff ff 89 fd 48 c7 c7 40 91 bf 96 e8 7d 89 7a 00
RSP: 0018:ffffc900032e7988 EFLAGS: 00000206
RAX: 0000000000000004 RBX: dffffc0000000000 RCX: ffffffff96bf9103
RDX: ffffc900032e7a01 RSI: dffffc0000000000 RDI: 0000000000000001
RBP: dffffc0000000000 R08: ffffc900032e7f10 R09: ffffc900032e7a98
R10: dffffc0000000000 R11: fffff5200065cf55 R12: ffffc900032e0000
R13: dffffc0000000000 R14: ffffc900032e7a58 R15: ffffc900032e7f20
 unwind_next_frame+0x1719/0x1fd0 arch/x86/kernel/unwind_orc.c:629
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 task_work_add+0x7f/0x330 kernel/task_work.c:48
 fput+0xd9/0x1a0 fs/file_table.c:376
 filp_close+0x108/0x150 fs/open.c:1439
 __do_sys_close fs/open.c:1452 [inline]
 __se_sys_close fs/open.c:1450 [inline]
 __x64_sys_close+0x34/0x70 fs/open.c:1450
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6f2ab9ce59
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:00007f6f2ba6e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f6f2ae15fa0 RCX: 00007f6f2ab9ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f6f2ac32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6f2ae16038 R14: 00007f6f2ae15fa0 R15: 00007ffc6ef0cec8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/06/20 04:39 linux-6.1.y fdb6fcb41cc7 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_close
* Struck through repros no longer work on HEAD.