INFO: rcu detected stall in sys_unlink (5)

Status: upstream: reported on 2025/09/25 16:42
Reported-by: syzbot+5854e0c59e957bb696cd@syzkaller.appspotmail.com
First crash: 358d, last: 8h44m
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sys_unlink (4) 1 1 535d 535d 0/3 auto-obsoleted due to no activity on 2025/07/10 21:02
linux-5.15 INFO: rcu detected stall in sys_unlink (3) 1 1 684d 684d 0/3 auto-obsoleted due to no activity on 2025/02/11 14:08
upstream INFO: rcu detected stall in sys_unlink (2) kernel 1 2 1335d 1420d 0/29 auto-obsoleted due to no activity on 2023/04/22 20:06
upstream INFO: rcu detected stall in sys_unlink (3) mm 1 syz, C error 425 1d23h 1132d 0/29 upstream: reported C repro on 2023/08/13 23:42
linux-6.1 INFO: rcu detected stall in sys_unlink (2) 1 36 1d07h 540d 0/3 upstream: reported on 2025/03/27 11:38
linux-6.1 INFO: rcu detected stall in sys_unlink 1 4 751d 969d 0/3 auto-obsoleted due to no activity on 2024/12/07 03:28
linux-5.15 INFO: rcu detected stall in sys_unlink (2) 1 3 803d 814d 0/3 auto-obsoleted due to no activity on 2024/10/15 13:02
linux-6.6 INFO: rcu detected stall in sys_unlink 1 49 2d14h 425d 0/2 upstream: reported on 2025/07/20 18:19
upstream INFO: rcu detected stall in sys_unlink mm kasan 1 1 1510d 1510d 0/29 auto-obsoleted due to no activity on 2022/10/29 07:23
linux-5.15 INFO: rcu detected stall in sys_unlink 1 1 920d 920d 0/3 auto-obsoleted due to no activity on 2024/06/20 14:47
android-5-15 BUG: soft lockup in sys_unlink 1 7 863d 885d 0/2 auto-obsoleted due to no activity on 2024/08/07 01:29

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (2 GPs behind) idle=d3d/1/0x4000000000000000 softirq=10003/10005 fqs=1 
	(detected by 0, t=10503 jiffies, g=11769, q=227)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4294 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:101 [inline]
RIP: 0010:do_raw_spin_unlock+0x77/0x230 kernel/locking/spinlock_debug.c:140
Code: c1 e8 03 42 0f b6 04 20 84 c0 0f 85 6f 01 00 00 83 3b 00 0f 84 e5 00 00 00 4c 8d 73 10 4d 89 f5 49 c1 ed 03 43 80 7c 25 00 00 <74> 08 4c 89 f7 e8 af 03 60 00 65 48 8b 05 07 2b a4 7e 49 39 06 0f
RSP: 0018:ffffc90000dd0c88 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffffff964f5d70 RCX: ffffffff815e4479
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff964f5d70
RBP: ffffc90000dd0d50 R08: ffffffff964f5d73 R09: 1ffffffff2c9ebae
R10: dffffc0000000000 R11: fffffbfff2c9ebaf R12: dffffc0000000000
R13: 1ffffffff2c9ebb0 R14: ffffffff964f5d80 R15: 1ffff920001ba198
FS:  00007fdf30d6f880(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3463f1 CR3: 000000001f23b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:159 [inline]
 _raw_spin_unlock_irqrestore+0x75/0x120 kernel/locking/spinlock.c:194
 debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1653 [inline]
 __hrtimer_run_queues+0x2c0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:call_rcu+0x697/0x900 kernel/rcu/tree.c:3092
Code: f7 84 24 a0 00 00 00 00 02 00 00 43 c6 44 25 04 f8 75 4f f7 44 24 58 00 02 00 00 74 01 fb 48 c7 84 24 80 00 00 00 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc90003347c20 EFLAGS: 00000206
RAX: afc3df8403255200 RBX: ffff88805d807730 RCX: afc3df8403255200
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffc90003347d50 R08: ffffffff901f1177 R09: 1ffffffff203e22e
R10: dffffc0000000000 R11: fffffbfff203e22f R12: dffffc0000000000
R13: 1ffff92000668f94 R14: ffff8880b913b2d0 R15: 0000000000000041
 __dentry_kill+0x4db/0x630 fs/dcache.c:600
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xd8/0x1a0 fs/dcache.c:893
 do_unlinkat+0x3a6/0x710 fs/namei.c:4402
 __do_sys_unlink fs/namei.c:4447 [inline]
 __se_sys_unlink fs/namei.c:4445 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4445
 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: 0033:0x7fdf30ecb937
Code: 00 00 e9 a9 fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 5f 00 00 00 0f 05 c3 0f 1f 84 00 00 00 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 91 b4 0d 00 f7 d8 64 89 02 b8
RSP: 002b:00007ffeefa04f98 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 000055fd86ef8320 RCX: 00007fdf30ecb937
RDX: 0000000000000001 RSI: 000055fd5d93c67f RDI: 00007ffeefa04fa0
RBP: 000000000000013b R08: 0000000000000064 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffeefa04fa0
R13: 0000000003938700 R14: 000055fd5d957100 R15: 000055fd5d957140
 </TASK>
rcu: rcu_preempt kthread starved for 10501 jiffies! g11769 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:28112 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:
NMI backtrace for cpu 0
CPU: 0 PID: 4975 Comm: syz.1.222 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xba3/0xd80 kernel/smp.c:969
Code: 0f b6 44 05 00 84 c0 0f 85 9a 00 00 00 41 8b 1e 89 de 83 e6 01 31 ff e8 ab 76 0b 00 83 e3 01 75 07 e8 41 73 0b 00 eb 42 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 10 41 f7
RSP: 0018:ffffc90002f9f2a0 EFLAGS: 00000246
RAX: ffffffff816da185 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc90003ca3000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90002f9f3e0 R08: ffffffff901f10cf R09: 1ffffffff203e219
R10: dffffc0000000000 R11: fffffbfff203e21a R12: ffff8880b903b3c0
R13: 1ffff110172280b9 R14: ffff8880b91405c8 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134
 __purge_vmap_area_lazy+0x21e/0x1940 mm/vmalloc.c:1690
 _vm_unmap_aliases+0x40b/0x4a0 mm/vmalloc.c:2114
 change_page_attr_set_clr+0x317/0xc30 arch/x86/mm/pat/set_memory.c:1740
 change_page_attr_clear arch/x86/mm/pat/set_memory.c:1797 [inline]
 set_memory_ro+0x89/0xd0 arch/x86/mm/pat/set_memory.c:1943
 bpf_jit_binary_lock_ro include/linux/filter.h:919 [inline]
 bpf_int_jit_compile+0xbf27/0xc4d0 arch/x86/net/bpf_jit_comp.c:2478
 bpf_prog_select_runtime+0x46f/0x7b0 kernel/bpf/core.c:1982
 bpf_prog_load+0x100a/0x14e0 kernel/bpf/syscall.c:2358
 __sys_bpf+0x532/0x6f0 kernel/bpf/syscall.c:4657
 __do_sys_bpf kernel/bpf/syscall.c:4761 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:4759 [inline]
 __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4759
 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: 0033:0x7fae04ffa159
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:00007fae03252028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fae05281fa0 RCX: 00007fae04ffa159
RDX: 0000000000000080 RSI: 00002000000003c0 RDI: 0000000000000005
RBP: 00007fae0509106b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fae05282038 R14: 00007fae05281fa0 R15: 00007ffdf3a30958
 </TASK>

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/18 20:59 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/09/04 20:22 linux-5.15.y 0996e0926f6b f65209a4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/08/25 05:47 linux-5.15.y 945fa863f02c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/08/21 23:00 linux-5.15.y 0eb903b5b519 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/08/17 16:50 linux-5.15.y aabd761612db 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/08/11 22:34 linux-5.15.y aabd761612db 71790083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/07/19 06:07 linux-5.15.y c86c4726e7f0 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/05/15 07:44 linux-5.15.y de8dfb3f0278 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/05/15 07:35 linux-5.15.y de8dfb3f0278 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/05/15 07:33 linux-5.15.y de8dfb3f0278 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/04/27 13:34 linux-5.15.y b9d57c40a767 0f700595 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/02/14 01:09 linux-5.15.y e45d5d41c134 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/02/09 15:49 linux-5.15.y 7b232985052f df949cd9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/01/17 18:50 linux-5.15.y 68efe5a6c16a 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2025/12/12 23:13 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2025/12/09 06:00 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2025/09/25 16:42 linux-5.15.y 43bb85222e53 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_unlink
* Struck through repros no longer work on HEAD.