INFO: rcu detected stall in sys_unlink (2)

Status: upstream: reported on 2025/03/27 11:38
Reported-by: syzbot+a0dc8f91386bb1406734@syzkaller.appspotmail.com
First crash: 520d, last: 11d
▶ ▼ 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 514d 514d 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 664d 664d 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 1314d 1399d 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 417 3d00h 1111d 0/29 upstream: reported C repro on 2023/08/13 23:42
linux-5.15 INFO: rcu detected stall in sys_unlink (5) 1 15 4d10h 337d 0/3 upstream: reported on 2025/09/25 16:42
linux-6.1 INFO: rcu detected stall in sys_unlink 1 4 730d 949d 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 783d 794d 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 47 11d 404d 0/2 upstream: reported on 2025/07/20 18:19
upstream INFO: rcu detected stall in sys_unlink mm kasan 1 1 1490d 1490d 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 900d 900d 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 842d 864d 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: 	0-...!: (1 GPs behind) idle=c404/1/0x4000000000000000 softirq=96091/96092 fqs=169
	(detected by 1, t=10502 jiffies, g=139181, q=1186 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 14181 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:check_preemption_disabled+0x2e/0x110 lib/smp_processor_id.c:55
Code: 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65 8b 05 91 ec d1 75 65 8b 0d 32 42 d2 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
RSP: 0018:ffffc90000007b68 EFLAGS: 00000006
RAX: 0000000000000000 RBX: 73039df9a44f64b2 RCX: 0000000000010003
RDX: 0000000000000002 RSI: ffffffff8a8c2920 RDI: ffffffff8adf5de0
RBP: ffffc90000007cb0 R08: ffffffff8e210aef R09: 1ffffffff1c4215d
R10: dffffc0000000000 R11: fffffbfff1c4215e R12: ffff88802d9e2930
R13: dffffc0000000000 R14: ffff88802d9e28d0 R15: 1ffff92000000f80
FS:  000055557ed86500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f41bf3f3e80 CR3: 0000000067292000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
 lock_release+0x558/0x920 kernel/locking/lockdep.c:5698
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x6d/0x120 kernel/locking/spinlock.c:194
 __run_hrtimer kernel/time/hrtimer.c:1747 [inline]
 __hrtimer_run_queues+0x421/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae 45 2a f7 48 89 df e8 36 0d 2b f7 e8 21 5e 4e f7 fb bf 01 00 00 00 <e8> b6 88 1e f7 65 8b 05 27 3a c8 75 85 c0 74 02 5b c3 e8 34 4e c6
RSP: 0018:ffffc900032978d8 EFLAGS: 00000286
RAX: ca34c41d0e635a00 RBX: ffff888079c53c40 RCX: ca34c41d0e635a00
RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: 0000000000000001
RBP: ffffc90003297b90 R08: ffffffff90b1024f R09: 1ffffffff2162049
R10: dffffc0000000000 R11: fffffbfff216204a R12: dffffc0000000000
R13: 1ffff1100f38a787 R14: ffff888079c53c38 R15: ffff888079c53c40
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 filemap_remove_folio+0xf5/0x2c0 mm/filemap.c:256
 truncate_inode_folio+0x59/0x70 mm/truncate.c:195
 shmem_undo_range+0x554/0x21d0 mm/shmem.c:942
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x225/0x9f0 mm/shmem.c:1171
 evict+0x4b6/0x8b0 fs/inode.c:705
 do_unlinkat+0x388/0x580 fs/namei.c:4405
 __do_sys_unlink fs/namei.c:4446 [inline]
 __se_sys_unlink fs/namei.c:4444 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4444
 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: 0033:0x7eff8319d1c7
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffc3a3bab68 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007eff8319d1c7
RDX: 00007ffc3a3bab90 RSI: 00007ffc3a3bac20 RDI: 00007ffc3a3bac20
RBP: 00007ffc3a3bac20 R08: 00007ffc3a3bbc20 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc3a3bbcb0
R13: 00007eff83234474 R14: 00000000001ca622 R15: 00007ffc3a3bbcf0
 </TASK>
rcu: rcu_preempt kthread starved for 10163 jiffies! g139181 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27888 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 4330 Comm: kworker/u4:7 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0x1148/0x1250 kernel/smp.c:998
Code: 41 8b 1f 89 de 83 e6 01 31 ff e8 73 ff 0a 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 0a e8 ff fb 0a 00 e9 34 ff ff ff f3 90 <41> 0f b6 04 1c 84 c0 75 14 41 f7 07 01 00 00 00 0f 84 17 ff ff ff
RSP: 0018:ffffc90004077800 EFLAGS: 00000293
RAX: ffffffff81773243 RBX: dffffc0000000000 RCX: ffff888025ba0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004077960 R08: ffffffff90b10247 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: 1ffff110171c8641
R13: ffff8880b8f3bdc0 R14: 0000000000000000 R15: ffff8880b8e43208
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000140 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x793/0x850 arch/x86/kernel/alternative.c:-1
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (32):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 11:08 linux-6.1.y e4f7d8be268e 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/08/14 14:58 linux-6.1.y e4f7d8be268e 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/07/30 22:07 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/07/27 06:13 linux-6.1.y dc5c83b7f5f8 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/07/09 09:36 linux-6.1.y 090666d3cc90 b9f1ceaa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/05/30 11:03 linux-6.1.y dcbcab9d7079 6b4a8443 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/05/21 17:47 linux-6.1.y c27210688955 e195359d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/05/10 08:07 linux-6.1.y ad16b162f21d 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/04/15 23:03 linux-6.1.y 8e8fc038cad5 c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/02/24 20:57 linux-6.1.y 779f9571ac3e 96b1aa46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/02/21 03:34 linux-6.1.y 779f9571ac3e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/02/12 10:28 linux-6.1.y 8ce36b2849ef 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/02/10 17:51 linux-6.1.y 0182cb5b74ee 91d776d3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/02/01 14:55 linux-6.1.y cd9b81672742 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/01/31 23:55 linux-6.1.y cd9b81672742 afc0c4d4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/01/31 23:53 linux-6.1.y cd9b81672742 afc0c4d4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/01/31 23:48 linux-6.1.y cd9b81672742 afc0c4d4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/01/27 21:55 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/01/27 21:48 linux-6.1.y cd9b81672742 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2026/01/26 20:41 linux-6.1.y cd9b81672742 a4c52dd6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/12/10 18:37 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/11/05 11:26 linux-6.1.y f6e38ae624cf a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/10/30 12:43 linux-6.1.y f6e38ae624cf fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/10/25 09:55 linux-6.1.y 8e6e2188d949 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/09/24 01:47 linux-6.1.y 363a599da6d9 e667a34f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/09/20 02:49 linux-6.1.y 363a599da6d9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/09/10 06:06 linux-6.1.y f97f1002271b fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/09/08 18:04 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/08/07 20:45 linux-6.1.y 3594f306da12 04cffc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/05/07 14:34 linux-6.1.y ac7079a42ea5 350f4ffc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_unlink
2025/04/10 09:45 linux-6.1.y 3dfebb87d7eb 988b336c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2025/03/27 11:38 linux-6.1.y 344a09659766 20510e88 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
* Struck through repros no longer work on HEAD.