INFO: rcu detected stall in sys_unlink

Status: auto-obsoleted due to no activity on 2024/12/07 03:28
Reported-by: syzbot+22bb0b3dbc38b0c7d00c@syzkaller.appspotmail.com
First crash: 987d, last: 769d
▶ ▼ 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 553d 553d 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 702d 702d 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 1353d 1438d 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 440 11h04m 1150d 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 2d12h 558d 0/3 upstream: reported C repro on 2025/03/27 11:38
linux-5.15 INFO: rcu detected stall in sys_unlink (5) 1 18 2d23h 376d 0/3 upstream: reported on 2025/09/25 16:42
linux-5.15 INFO: rcu detected stall in sys_unlink (2) 1 3 821d 832d 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 52 4d04h 443d 0/2 upstream: reported on 2025/07/20 18:19
upstream INFO: rcu detected stall in sys_unlink mm kasan 1 1 1528d 1528d 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 938d 938d 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 881d 903d 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): P5869/1:b..l P3092/1:b..l
	(detected by 0, t=10502 jiffies, g=18177, q=20 ncpus=2)
task:udevd           state:R  running task     stack:24600 pid:3092  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:__legitimize_mnt+0x0/0x190 fs/namespace.c:624
Code: 8b 34 24 48 c7 c7 48 47 01 8d e8 eb 06 71 ff ff 05 85 b5 07 0b 48 c7 c7 78 47 01 8d e9 49 3a b6 08 66 0f 1f 84 00 00 00 00 00 <55> 41 57 41 56 41 55 41 54 53 89 f5 49 89 ff e8 dc 11 91 ff 8b 1d
RSP: 0018:ffffc9000318fb00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff92000631f84 RCX: 1ffff92000631f8d
RDX: 0000000000000000 RSI: 0000000000001e62 RDI: ffff88813fe4fca0
RBP: 0000000000001e62 R08: ffffffff81f544d6 R09: fffff52000631f86
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000631f85
R13: ffffc9000318fc20 R14: ffffc9000318fc28 R15: dffffc0000000000
 __legitimize_path fs/namei.c:701 [inline]
 legitimize_path fs/namei.c:718 [inline]
 try_to_unlazy+0xf3/0x5b0 fs/namei.c:779
 complete_walk+0x118/0x360 fs/namei.c:888
 path_parentat fs/namei.c:2528 [inline]
 __filename_parentat+0x27e/0x6e0 fs/namei.c:2550
 filename_parentat fs/namei.c:2568 [inline]
 do_unlinkat+0x185/0x820 fs/namei.c:4363
 __do_sys_unlink fs/namei.c:4440 [inline]
 __se_sys_unlink fs/namei.c:4438 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4438
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0369917da7
RSP: 002b:00007ffda0668408 EFLAGS: 00000202 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0369917da7
RDX: 0000000000000001 RSI: 00007ffda06684e0 RDI: 000055c26374f0d8
RBP: 0000000000000000 R08: 000000000f88bea9 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000bb8
R13: 0000000200000001 R14: 0000000000000001 R15: 0000000000000000
 </TASK>
task:syz.3.490       state:R  running task     stack:24376 pid:5869  ppid:3645   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 preempt_schedule_notrace+0xf8/0x140 kernel/sched/core.c:6820
 preempt_schedule_notrace_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35
 rcu_is_watching+0x76/0xb0 kernel/rcu/tree.c:722
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xfa/0x5a0 kernel/locking/lockdep.c:5633
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 dput+0x54/0x1d0 fs/dcache.c:904
 __fput+0x62e/0x8d0 fs/file_table.c:328
 task_work_run+0x246/0x300 kernel/task_work.c:203
 get_signal+0x15fc/0x17d0 kernel/signal.c:2647
 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb71eb79ef9
RSP: 002b:00007ffc7b6e6808 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fb71ed17a80 RCX: 00007fb71eb79ef9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fb71ed17a80 R08: 0000000000000006 R09: 00007ffc7b6e6aff
R10: 00000000003ff7d4 R11: 0000000000000246 R12: 000000000003e9a4
R13: 00007ffc7b6e6910 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>
rcu: rcu_preempt kthread starved for 10558 jiffies! g18177 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:26136 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5873 Comm: syz.1.492 Not tainted 6.1.106-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:__lock_acquire+0x381/0x1f80 kernel/locking/lockdep.c:4986
Code: a2 77 00 48 8b 34 24 48 ba 00 00 00 00 00 fc ff df 4c 89 33 48 89 6c 24 20 48 8d 5c ee 18 48 89 d8 48 c1 e8 03 48 89 44 24 70 <80> 3c 10 00 4c 8b 6c 24 48 74 16 48 89 df e8 9c a2 77 00 48 8b 34
RSP: 0018:ffffc9000332f880 EFLAGS: 00000802
RAX: 1ffff1100f9098d9 RBX: ffff88807c84c6c8 RCX: ffff88807c84bb80
RDX: dffffc0000000000 RSI: ffff88807c84c660 RDI: ffffffff8d32afc0
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffffffff81e170ee R14: ffffffff8d32afc0 R15: 000000000000002c
FS:  00007ff4e23926c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe9fdd8f80 CR3: 000000005b162000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 percpu_ref_get_many include/linux/percpu-refcount.h:202 [inline]
 percpu_ref_get include/linux/percpu-refcount.h:222 [inline]
 obj_cgroup_get include/linux/memcontrol.h:784 [inline]
 memcg_slab_post_alloc_hook mm/slab.h:535 [inline]
 slab_post_alloc_hook+0x1bb/0x3a0 mm/slab.h:745
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
 __sigqueue_alloc+0x42e/0x540 kernel/signal.c:435
 __send_signal_locked+0x22f/0xdc0 kernel/signal.c:1128
 do_send_sig_info kernel/signal.c:1300 [inline]
 group_send_sig_info+0x28a/0x300 kernel/signal.c:1448
 bpf_send_signal_common+0x2d8/0x420 kernel/trace/bpf_trace.c:882
 ____bpf_send_signal kernel/trace/bpf_trace.c:887 [inline]
 bpf_send_signal+0x15/0x20 kernel/trace/bpf_trace.c:885
 bpf_prog_7ba5217f62dcd359+0x38/0x3c
 bpf_dispatcher_nop_func include/linux/bpf.h:989 [inline]
 __bpf_prog_run include/linux/filter.h:603 [inline]
 bpf_prog_run include/linux/filter.h:610 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2273 [inline]
 bpf_trace_run2+0x1fd/0x410 kernel/trace/bpf_trace.c:2312
 __bpf_trace_sys_enter+0x60/0x70 include/trace/events/syscalls.h:18
 trace_sys_enter include/trace/events/syscalls.h:18 [inline]
 syscall_trace_enter kernel/entry/common.c:81 [inline]
 __syscall_enter_from_user_work kernel/entry/common.c:100 [inline]
 syscall_enter_from_user_mode+0x206/0x230 kernel/entry/common.c:118
 do_syscall_64+0x1e/0xb0 arch/x86/entry/common.c:77
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff4e1515849
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ff4e2391a80 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007ff4e1715f80 RCX: 00007ff4e1515849
RDX: 00007ff4e2391a80 RSI: 00007ff4e2391bb0 RDI: 0000000000000011
RBP: 00007ff4e15e793e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007ff4e1715f80 R15: 00007ffe9fdd91d8
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/29 03:27 linux-6.1.y ee5e09825b81 ef3de9e8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2024/06/17 04:31 linux-6.1.y eb44d83053d6 f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2024/04/02 14:52 linux-6.1.y e5cd595e23c1 eb2966c4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_unlink
2024/01/23 10:49 linux-6.1.y 8fd7f4462453 1c0ecc51 .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.