INFO: rcu detected stall in sys_close (3)

Status: upstream: reported on 2026/08/07 05:33
Reported-by: syzbot+dc50b5808acc0ec1955d@syzkaller.appspotmail.com
First crash: 16h05m, last: 16h05m
▶ ▼ Similar bugs (12)
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 1442d 1442d 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 263d 263d 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 1365d 1365d 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 832d 832d 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 syz, C error 2 220d 240d 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 syz, C error 21 43d 840d 0/29 upstream: reported C repro on 2024/04/19 01:14
linux-6.1 INFO: rcu detected stall in sys_close (2) 1 1 48d 48d 0/3 upstream: reported on 2026/06/20 04:40
linux-6.1 INFO: rcu detected stall in sys_close origin:lts-only 1 syz, C done 1 246d 277d 3/3 fixed on 2026/01/11 15:32
upstream INFO: rcu detected stall in sys_close fs 1 1 1680d 1680d 0/29 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in sys_close (6) fs 1 3 939d 1020d 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 1537d 1587d 0/29 auto-closed as invalid on 2022/08/21 03:13
upstream INFO: rcu detected stall in sys_close (5) net 1 syz, C done 1 1074d 1074d 23/29 fixed on 2023/10/12 12:48

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3559/1:b..l
	(detected by 1, t=10502 jiffies, g=88569, q=313)
task:udevd           state:R  running task     stack:22960 pid: 3559 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90002d9f920 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 7654b00d828db000
RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a4200
RBP: ffffc90002d9fa40 R08: dffffc0000000000 R09: 1ffffffff203dc18
R10: dffffc0000000000 R11: fffffbfff203dc19 R12: ffffffff8c31ef60
R13: 1ffff920005b3f30 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 is_bpf_text_address+0x1d/0x270 kernel/bpf/core.c:725
 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+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 task_work_add+0x2f/0x1d0 kernel/task_work.c:38
 fput_many+0xde/0x1a0 fs/file_table.c:367
 filp_close+0x10e/0x150 fs/open.c:1371
 __do_sys_close fs/open.c:1384 [inline]
 __se_sys_close fs/open.c:1382 [inline]
 __x64_sys_close+0x34/0x70 fs/open.c:1382
 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: 0033:0x7fa43aab2a67
RSP: 002b:00007ffee8960688 EFLAGS: 00000206 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000564e6f372110 RCX: 00007fa43aab2a67
RDX: 0000000000009c11 RSI: 00007fa43ab8eb20 RDI: 000000000000000d
RBP: 0000564e6f305c90 R08: 0000000000001bd0 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000206 R12: 0000564e6f3007b0
R13: 00000000000000ff R14: 0000564e59f76be0 R15: 00007ffee8960930
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g88569 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=38727
rcu: rcu_preempt kthread starved for 10502 jiffies! g88569 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27440 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 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/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: bat_events batadv_nc_worker
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:87 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x8a/0x290 mm/kasan/generic.c:189
Code: 1c 21 49 89 df 4d 29 df 49 83 ff 10 7f 29 4d 85 ff 0f 84 38 01 00 00 4c 89 cb 48 f7 d3 4c 01 f3 41 80 3b 00 0f 85 86 01 00 00 <49> ff c3 48 ff c3 75 ee e9 18 01 00 00 44 89 dd 83 e5 07 0f 84 b5
RSP: 0018:ffffc90000007030 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff815cdb46
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d8b0de8
RBP: ffffc90000007178 R08: ffffffff8d8b0def R09: 1ffffffff1b161bd
R10: dffffc0000000000 R11: fffffbfff1b161bd R12: dffffc0000000001
R13: 1ffff92000000e18 R14: 1ffffffff1b161bd R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3bda15fa10 CR3: 00000000647ba000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 cpumask_test_cpu include/linux/cpumask.h:344 [inline]
 cpu_online include/linux/cpumask.h:895 [inline]
 trace_lock_acquire include/trace/events/lock.h:13 [inline]
 lock_acquire+0xb6/0x400 kernel/locking/lockdep.c:5594
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 __perf_event_output kernel/events/core.c:7800 [inline]
 perf_event_output_forward+0xbc/0x2e0 kernel/events/core.c:7822
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9515
 perf_swevent_overflow kernel/events/core.c:9591 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9629
 perf_tp_event+0x324/0xbe0 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 02 20 9d 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:ffffc90000007820 EFLAGS: 00000206
RAX: aa60e13a824e3600 RBX: 1ffff92000000f08 RCX: aa60e13a824e3600
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4200
RBP: ffffc90000007900 R08: ffffffff901ee18f R09: 1ffffffff203dc31
R10: dffffc0000000000 R11: fffffbfff203dc32 R12: ffffffff8c323400
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+0x1288/0x1ce0 net/ipv4/ip_output.c:539
 __tcp_transmit_skb+0x1ca3/0x31e0 net/ipv4/tcp_output.c:1404
 tcp_delack_timer_handler+0x2f8/0x700 net/ipv4/tcp_timer.c:314
 tcp_delack_timer+0x18d/0x2f0 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+0x56c/0x810 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x336/0x830 kernel/softirq.c:576
 do_softirq+0x142/0x210 kernel/softirq.c:477
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x180/0x1c0 kernel/softirq.c:401
 spin_unlock_bh include/linux/spinlock.h:409 [inline]
 batadv_nc_purge_paths+0x305/0x3a0 net/batman-adv/network-coding.c:475
 batadv_nc_worker+0x321/0x5c0 net/batman-adv/network-coding.c:726
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/07 05:33 linux-5.15.y 9c7634c60784 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_close
* Struck through repros no longer work on HEAD.