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: 404d, last: 9d10h
▶ ▼ 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 581d 581d 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 730d 730d 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 1381d 1466d 0/29 auto-obsoleted due to no activity on 2023/04/22 20:06
upstream INFO: rcu detected stall in sys_unlink (3) tomoyo 1 syz, C error 458 22h10m 1178d 0/29 upstream: reported C repro on 2023/08/13 23:42
linux-6.1 INFO: rcu detected stall in sys_unlink (2) 1 syz, C 38 30d 586d 0/3 upstream: reported C repro on 2025/03/27 11:38
linux-6.1 INFO: rcu detected stall in sys_unlink 1 4 797d 1015d 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 849d 860d 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 56 7d17h 471d 0/2 upstream: reported on 2025/07/20 18:19
upstream INFO: rcu detected stall in sys_unlink mm kasan 1 1 1557d 1557d 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 966d 966d 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 909d 931d 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: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4189/1:b..l
	(detected by 1, t=10502 jiffies, g=11489, q=149)
task:syz-executor    state:R  running task     stack:21872 pid: 4189 ppid:  4185 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:435
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x209/0x400 kernel/locking/lockdep.c:5741
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90002dff6e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0d1a09efb79df100
RDX: 0000000000000000 RSI: ffffffff8a2b3e00 RDI: ffffffff8a7a4bc0
RBP: ffffc90002dff800 R08: dffffc0000000000 R09: 1ffffffff2208c18
R10: dffffc0000000000 R11: fffffbfff2208c19 R12: 1ffff920005bfee8
R13: ffffffff8d11efa0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 find_lock_entries+0xf7/0xd70 mm/filemap.c:2091
 shmem_undo_range+0x292/0x19a0 mm/shmem.c:943
 shmem_truncate_range mm/shmem.c:1063 [inline]
 shmem_evict_inode+0x1e2/0x9a0 mm/shmem.c:1145
 evict+0x4b6/0x8b0 fs/inode.c:647
 do_unlinkat+0x3e7/0x710 fs/namei.c:4406
 __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: 0033:0x7f2941c3e647
RSP: 002b:00007ffd770cf838 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2941c3e647
RDX: 00007ffd770cf860 RSI: 00007ffd770cf8f0 RDI: 00007ffd770cf8f0
RBP: 00007ffd770cf8f0 R08: 00007ffd770d08f0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd770d0980
R13: 00007f2941cd5f63 R14: 000000000001ec5a R15: 00007ffd770d09c0
 </TASK>
rcu: rcu_preempt kthread starved for 9912 jiffies! g11489 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:27488 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 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/25 21:07 linux-5.15.y 792fbe1537d8 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/10/22 16:42 linux-5.15.y 792fbe1537d8 b55fad29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
2026/10/04 04:37 linux-5.15.y a051a4bf909f 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
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.