INFO: rcu detected stall in sys_symlinkat (5)

Status: upstream: reported on 2026/09/11 05:55
Reported-by: syzbot+8992d39728447d01b11c@syzkaller.appspotmail.com
First crash: 1d09h, last: 1d09h
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_symlinkat (3) ext4 1 3 1141d 1194d 0/29 auto-obsoleted due to no activity on 2023/10/26 22:46
linux-6.1 INFO: rcu detected stall in sys_symlinkat (3) origin:upstream 1 syz error 5 91d 497d 0/3 upstream: reported syz repro on 2025/05/03 06:00
linux-5.15 INFO: rcu detected stall in sys_symlinkat 1 1 1204d 1204d 0/3 auto-obsoleted due to no activity on 2023/09/03 15:54
linux-5.15 INFO: rcu detected stall in sys_symlinkat (3) 1 2 816d 842d 0/3 auto-obsoleted due to no activity on 2024/09/25 17:37
upstream INFO: rcu detected stall in sys_symlinkat (5) prio:normal tomoyo 1 syz error error 124 1d12h 647d 0/29 upstream: reported syz repro on 2024/12/04 02:45
linux-6.1 INFO: rcu detected stall in sys_symlinkat (2) 1 1 989d 989d 0/3 auto-obsoleted due to no activity on 2024/04/06 00:16
upstream INFO: rcu detected stall in sys_symlinkat kvm 1 5 1474d 1574d 0/29 auto-obsoleted due to no activity on 2022/11/28 07:06
linux-6.1 INFO: rcu detected stall in sys_symlinkat 1 1 1234d 1234d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:07
upstream INFO: rcu detected stall in sys_symlinkat (2) ext4 lsm 1 2 1287d 1380d 0/29 auto-obsoleted due to no activity on 2023/06/03 10:14
upstream INFO: rcu detected stall in sys_symlinkat (4) ext4 1 1 1018d 1018d 0/29 auto-obsoleted due to no activity on 2024/02/27 04:07
linux-5.15 INFO: rcu detected stall in sys_symlinkat (4) 1 2 233d 255d 0/3 auto-obsoleted due to no activity on 2026/05/02 14:14
linux-6.6 INFO: rcu detected stall in sys_symlinkat 1 1 196d 196d 0/2 auto-obsoleted due to no activity on 2026/06/08 11:28
linux-5.15 INFO: rcu detected stall in sys_symlinkat (2) 1 1 1014d 1014d 0/3 auto-obsoleted due to no activity on 2024/03/12 11:22
android-5-15 BUG: soft lockup in sys_symlinkat 1 13 789d 880d 0/2 auto-obsoleted due to no activity on 2024/10/13 01:26

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 ticks this GP) idle=e1f/1/0x4000000000000002 softirq=21334/21334 fqs=0 
	(detected by 1, t=10502 jiffies, g=27129, q=1394)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8305 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kvm_is_in_guest+0x0/0x30 arch/x86/kvm/x86.c:8606
Code: d1 80 e1 07 80 c1 03 38 c1 0f 8c b7 fc ff ff 48 89 54 24 18 48 8b 7c 24 18 e8 5c 4c af 00 48 8b 54 24 18 e9 9e fc ff ff 66 90 <53> e8 8a 1e 6a 00 48 c7 c7 a0 56 22 8a e8 2e 94 b1 08 65 48 8b 1d
RSP: 0018:ffffc90000006e30 EFLAGS: 00000046
RAX: 1ffffffff1824ba0 RBX: ffff8880b90351c8 RCX: ffff888024671dc0
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffffc90000006fd7 R09: ffffc90000006fa0
R10: dffffc0000000000 R11: fffff52000000dfb R12: dffffc0000000000
R13: ffffc90000007006 R14: ffffffff8c125d00 R15: dffffc0000000000
FS:  0000555561953500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f573a67786c CR3: 0000000074f66000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_misc_flags+0x8f/0x1b0 arch/x86/events/core.c:2964
 perf_prepare_sample+0x132/0x1cb0 kernel/events/core.c:7632
 __perf_event_output kernel/events/core.c:7812 [inline]
 perf_event_output_forward+0x185/0x2e0 kernel/events/core.c:7832
 __perf_event_overflow+0x35f/0x550 kernel/events/core.c:9525
 perf_swevent_overflow kernel/events/core.c:9601 [inline]
 perf_swevent_event+0x4b8/0x540 kernel/events/core.c:9639
 perf_tp_event+0x324/0xbe0 kernel/events/core.c:10057
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 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 0f 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:ffffc90000007600 EFLAGS: 00000206
RAX: 53cf1c33d1c85e00 RBX: 1ffff92000000ec4 RCX: 53cf1c33d1c85e00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: ffffc900000076e0 R08: ffffffff901ef197 R09: 1ffffffff203de32
R10: dffffc0000000000 R11: fffffbfff203de33 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]
 ndisc_send_skb+0xd3b/0x1410 net/ipv6/ndisc.c:521
 ndisc_send_ns+0x662/0x860 net/ipv6/ndisc.c:655
 ndisc_solicit+0x300/0x4f0 net/ipv6/ndisc.c:747
 neigh_probe net/core/neighbour.c:1017 [inline]
 neigh_timer_handler+0xaa9/0xff0 net/core/neighbour.c:1099
 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 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:kasan_quarantine_put+0x84/0x210 mm/kasan/quarantine.c:234
Code: e8 81 f6 c0 ff 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 0f 85 83 00 00 00 41 f7 c7 00 02 00 00 74 01 fb 31 c0 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f c3 48 8d 80 40 62 03 00 45
RSP: 0018:ffffc9000139fa38 EFLAGS: 00000206
RAX: 53cf1c33d1c85e01 RBX: ffff888023b34980 RCX: 53cf1c33d1c85e00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: ffffc9000139fac8 R08: ffffffff901ef177 R09: 1ffffffff203de2e
R10: dffffc0000000000 R11: fffffbfff203de2f R12: ffff888016c41640
R13: ffff888023b34980 R14: 000000000007bd58 R15: 0000000000000282
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 tomoyo_path_perm+0x433/0x5d0 security/tomoyo/file.c:842
 tomoyo_path_symlink+0xa8/0xf0 security/tomoyo/tomoyo.c:199
 security_path_symlink+0xdc/0x130 security/security.c:1229
 do_symlinkat+0x105/0x6b0 fs/namei.c:4504
 __do_sys_symlinkat fs/namei.c:4526 [inline]
 __se_sys_symlinkat fs/namei.c:4523 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4523
 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: 0033:0x7f573a5b5217
Code: 44 00 00 48 89 f2 31 c9 48 89 fe bf 9c ff ff ff e9 8e f5 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0a 01 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:00007ffc0b6e1918 EFLAGS: 00000206 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f573a5b5217
RDX: 00007f573a64dffd RSI: 00000000ffffff9c RDI: 00007ffc0b6e19b0
RBP: 00007ffc0b6e195c R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000e1
R13: 00000000000927c0 R14: 0000000000039b9e R15: 00007ffc0b6e19b0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g27129 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=12155
rcu: rcu_preempt kthread starved for 10502 jiffies! g27129 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:27472 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: 8305 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:171 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x1b/0x60 kernel/kcov.c:205
Code: 89 de 5b e9 57 65 44 00 00 00 cc cc 00 00 cc 48 8b 04 24 65 48 8b 0d 14 60 89 7e 65 8b 15 15 60 89 7e 81 e2 00 01 ff 00 74 11 <81> fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00
RSP: 0018:ffffc90000007138 EFLAGS: 00000006
RAX: ffffffff81987e3a RBX: ffff8880b9035250 RCX: ffff888024671dc0
RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffff88805d62ee50
RBP: ffffc900000073c8 R08: ffffffff8d8b122f R09: 1ffffffff1b16245
R10: dffffc0000000000 R11: fffffbfff1b16246 R12: 1ffff11017206a4a
R13: ffff88805d62eb70 R14: 0000000000000000 R15: 0000000000000000
FS:  0000555561953500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f573a67786c CR3: 0000000074f66000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 perf_tp_filter_match kernel/events/core.c:9996 [inline]
 perf_tp_event_match kernel/events/core.c:10013 [inline]
 perf_tp_event+0x30a/0xbe0 kernel/events/core.c:10056
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10031
 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 0f 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:ffffc90000007600 EFLAGS: 00000206
RAX: 53cf1c33d1c85e00 RBX: 1ffff92000000ec4 RCX: 53cf1c33d1c85e00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: ffffc900000076e0 R08: ffffffff901ef197 R09: 1ffffffff203de32
R10: dffffc0000000000 R11: fffffbfff203de33 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]
 ndisc_send_skb+0xd3b/0x1410 net/ipv6/ndisc.c:521
 ndisc_send_ns+0x662/0x860 net/ipv6/ndisc.c:655
 ndisc_solicit+0x300/0x4f0 net/ipv6/ndisc.c:747
 neigh_probe net/core/neighbour.c:1017 [inline]
 neigh_timer_handler+0xaa9/0xff0 net/core/neighbour.c:1099
 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 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:kasan_quarantine_put+0x84/0x210 mm/kasan/quarantine.c:234
Code: e8 81 f6 c0 ff 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 0f 85 83 00 00 00 41 f7 c7 00 02 00 00 74 01 fb 31 c0 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f c3 48 8d 80 40 62 03 00 45
RSP: 0018:ffffc9000139fa38 EFLAGS: 00000206
RAX: 53cf1c33d1c85e01 RBX: ffff888023b34980 RCX: 53cf1c33d1c85e00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: ffffc9000139fac8 R08: ffffffff901ef177 R09: 1ffffffff203de2e
R10: dffffc0000000000 R11: fffffbfff203de2f R12: ffff888016c41640
R13: ffff888023b34980 R14: 000000000007bd58 R15: 0000000000000282
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kfree+0xef/0x2a0 mm/slub.c:4564
 tomoyo_path_perm+0x433/0x5d0 security/tomoyo/file.c:842
 tomoyo_path_symlink+0xa8/0xf0 security/tomoyo/tomoyo.c:199
 security_path_symlink+0xdc/0x130 security/security.c:1229
 do_symlinkat+0x105/0x6b0 fs/namei.c:4504
 __do_sys_symlinkat fs/namei.c:4526 [inline]
 __se_sys_symlinkat fs/namei.c:4523 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4523
 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: 0033:0x7f573a5b5217
Code: 44 00 00 48 89 f2 31 c9 48 89 fe bf 9c ff ff ff e9 8e f5 ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 0a 01 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:00007ffc0b6e1918 EFLAGS: 00000206 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f573a5b5217
RDX: 00007f573a64dffd RSI: 00000000ffffff9c RDI: 00007ffc0b6e19b0
RBP: 00007ffc0b6e195c R08: 0000000000000001 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000e1
R13: 00000000000927c0 R14: 0000000000039b9e R15: 00007ffc0b6e19b0
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/11 05:54 linux-5.15.y 0996e0926f6b 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_symlinkat
* Struck through repros no longer work on HEAD.