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INFO: rcu detected stall in sys_close

Status: upstream: reported C repro on 2025/11/03 07:00
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+709c47d251d42d0d843d@syzkaller.appspotmail.com
First crash: 48d, last: 17d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/11/03 linux-6.1.y (ToT) f6e38ae624cf C [report] INFO: rcu detected stall in corrupted
2025/11/03 upstream (ToT) 6146a0f1dfae C Didn't crash
▶ ▼ Similar bugs (10)
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 1213d 1213d 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 34d 34d 0/3 upstream: reported on 2025/11/17 04:01
upstream INFO: rcu detected stall in sys_close (4) fs 1 1 1136d 1136d 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 603d 603d 0/3 auto-obsoleted due to no activity on 2024/08/05 21:33
linux-6.6 INFO: rcu detected stall in close 1 C 1 11d 11d 0/2 upstream: reported C repro on 2025/12/10 03:57
upstream INFO: rcu detected stall in sys_close (7) fs 1 C error 14 28d 611d 0/29 upstream: reported C repro on 2024/04/19 01:14
upstream INFO: rcu detected stall in sys_close fs 1 1 1451d 1451d 0/29 closed as invalid on 2022/02/08 10:10
upstream INFO: rcu detected stall in sys_close (6) fs 1 3 710d 791d 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 1308d 1358d 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 845d 845d 23/29 fixed on 2023/10/12 12:48
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2025/12/04 17:52 2h16m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2657 jiffies s: 4313 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4283 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:check_preemption_disabled+0x4b/0x110 lib/smp_processor_id.c:55
Code: 0d 72 88 ea 75 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f <5d> c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 74
RSP: 0018:ffffc900001e07b0 EFLAGS: 00000082
RAX: 0000000000000001 RBX: 0000000000000014 RCX: a8032526509c3300
RDX: 0000000000000100 RSI: ffffffff8adef740 RDI: ffffffff8adef700
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffffed10171e6afa
R10: ffffed10171e6afa R11: 1ffff110171e6af9 R12: ffffffff8cb7d320
R13: dffffc0000000000 R14: ffffc900001e0840 R15: 00000000000000a8
FS:  00007fdf4f862880(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555910fc5c8 CR3: 000000001be93000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 perf_trace_buf_alloc+0xb4/0x300 kernel/trace/trace_event_perf.c:419
 perf_trace_preemptirq_template+0x149/0x330 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+0x84/0x500 kernel/rcu/tree_plugin.h:685
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 90 96 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001e09c0 EFLAGS: 00000206
RAX: a8032526509c3300 RBX: 1ffff9200003c140 RCX: a8032526509c3300
RDX: dffffc0000000000 RSI: ffffffff8a8c0580 RDI: ffffffff8adef760
RBP: ffffc900001e0ac0 R08: dffffc0000000000 R09: ffffed10171e6afa
R10: ffffed10171e6afa R11: 1ffff110171e6af9 R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 process_backlog+0x3ff/0x6e0 net/core/dev.c:6024
 __napi_poll+0xc0/0x460 net/core/dev.c:6590
 napi_poll net/core/dev.c:6657 [inline]
 net_rx_action+0x5b1/0xad0 net/core/dev.c:6771
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 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:unwind_next_frame+0x10a2/0x20b0 arch/x86/kernel/unwind_orc.c:569
Code: 8b 7c 24 10 74 05 e8 ad 90 98 00 48 8b 04 24 48 89 43 50 48 8d 7b 58 48 89 f8 48 c1 e8 03 42 80 3c 28 00 74 05 e8 8e 90 98 00 <48> c7 43 58 00 00 00 00 4c 8d 7b 36 4c 89 f8 48 c1 e8 03 42 0f b6
RSP: 0018:ffffc90003df7970 EFLAGS: 00000246
RAX: 1ffff920007bef54 RBX: ffffc90003df7a48 RCX: 1ffff920007bef01
RDX: ffffc90003df7f58 RSI: ffffffff8e96b828 RDI: ffffc90003df7aa0
RBP: ffffffff8f3a4ff4 R08: 0000000000000004 R09: 0000000000000007
R10: fffff520007bef55 R11: 1ffff920007bef53 R12: ffffc90003df7a7d
R13: dffffc0000000000 R14: ffffc90003df7a80 R15: 00007ffc6d7411c8
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486
 task_work_add+0x79/0x330 kernel/task_work.c:48
 fput+0xd9/0x1a0 fs/file_table.c:376
 filp_close+0x108/0x150 fs/open.c:1437
 __do_sys_close fs/open.c:1450 [inline]
 __se_sys_close fs/open.c:1448 [inline]
 __x64_sys_close+0x34/0x70 fs/open.c:1448
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdf4f115a67
Code: 44 00 00 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 01 31 c9 e8 ca 19 f9 ff 48 83 c4 18 c3 0f 1f 44 00 00 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 61 b3 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffc6d7411c8 EFLAGS: 00000297 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 000055cb9cc0bbd0 RCX: 00007fdf4f115a67
RDX: 00007fdf4f1efea0 RSI: 000055cb9cc0d550 RDI: 0000000000000008
RBP: 00007fdf4f1efff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000
R13: 3d45505954564544 R14: 3d5845444e494649 R15: 3d454d414e564544
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/03 07:00 linux-6.1.y f6e38ae624cf 2c50b6a9 .config console log report syz / log C [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.