INFO: rcu detected stall in sys_mkdirat (3)

Status: upstream: reported on 2025/11/05 18:14
Reported-by: syzbot+750ad6e3a9f8a2f1a88a@syzkaller.appspotmail.com
First crash: 337d, last: 26d
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in sys_mkdirat 1 2 685d 724d 0/3 auto-obsoleted due to no activity on 2025/03/02 02:09
linux-5.15 INFO: rcu detected stall in sys_mkdirat 1 1 1066d 1066d 0/3 auto-obsoleted due to no activity on 2024/02/15 18:20
linux-6.6 INFO: rcu detected stall in sys_mkdirat 1 1 1d22h 1d22h 0/2 upstream: reported on 2026/10/07 00:11
upstream INFO: rcu detected stall in sys_mkdirat ext4 net 1 3 1275d 1391d 0/29 auto-obsoleted due to no activity on 2023/07/11 04:05
upstream INFO: rcu detected stall in sys_mkdirat (2) mm 1 44 460d 661d 0/29 auto-obsoleted due to no activity on 2025/10/13 21:11
linux-6.1 INFO: rcu detected stall in sys_mkdirat (2) 1 6 54d 160d 0/3 upstream: reported on 2026/05/01 18:50
linux-5.15 INFO: rcu detected stall in sys_mkdirat (2) 1 1 587d 587d 0/3 auto-obsoleted due to no activity on 2025/06/08 06:38
android-5-15 BUG: soft lockup in sys_mkdirat 1 8 855d 906d 0/2 auto-obsoleted due to no activity on 2024/09/03 20:00

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=851/1/0x4000000000000002 softirq=79320/79321 fqs=5231 
	(detected by 1, t=10502 jiffies, g=117465, q=2665)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 24120 Comm: syz.6.6563 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__rcu_read_unlock+0x0/0xd0 kernel/rcu/tree_plugin.h:415
Code: c0 75 11 ff 03 8b 03 3d 00 00 00 40 7d 02 5b c3 0f 0b eb fa 89 d9 80 e1 07 80 c1 03 38 c1 7c e3 48 89 df e8 d2 de 58 00 eb d9 <41> 57 41 56 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b
RSP: 0018:ffffc900000071c8 EFLAGS: 00000046
RAX: ffffffff819bd978 RBX: 0000000000000001 RCX: ffff88804ab71dc0
RDX: 0000000000000100 RSI: ffffffff8a7a4520 RDI: ffffffff8a7a44e0
RBP: ffffc90000007310 R08: ffffc90000007297 R09: ffffc90000007280
R10: dffffc0000000000 R11: fffff52000000e53 R12: 1ffff92000000e4c
R13: ffffc90000007360 R14: dffffc0000000000 R15: ffff888078cf7760
FS:  00007f5ce1a4b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558fa2d0b8 CR3: 00000000619fb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 rcu_read_unlock+0x85/0x90 include/linux/rcupdate.h:772
 __perf_output_begin kernel/events/ring_buffer.c:262 [inline]
 perf_output_begin_forward+0x793/0xa30 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7814 [inline]
 perf_event_output_forward+0x19b/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:ffffc900000079c0 EFLAGS: 00000206
RAX: 86fa7f488ba79400 RBX: 1ffff92000000f3c RCX: 86fa7f488ba79400
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: ffffc90000007aa0 R08: ffffffff901ef1bf R09: 1ffffffff203de37
R10: dffffc0000000000 R11: fffffbfff203de38 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]
 hsr_announce+0x29a/0x310 net/hsr/hsr_device.c:410
 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:finish_lock_switch+0x12f/0x290 kernel/sched/core.c:4804
Code: 83 c7 18 be ff ff ff ff e8 0e 1b 6c 08 85 c0 74 46 4d 85 ff 75 62 0f 1f 44 00 00 48 89 df e8 c8 8a 75 08 e8 f3 df 2a 00 fb 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 2f 0e fe ff 43 80 3c 2c
RSP: 0018:ffffc9000323fa78 EFLAGS: 00000282
RAX: 86fa7f488ba79400 RBX: ffff88807d6e8000 RCX: 86fa7f488ba79400
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a4540
RBP: 1ffff11017207613 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 1ffff110172075c1
R13: dffffc0000000000 R14: ffff8880b903ae08 R15: 0000000000000000
 finish_task_switch+0x12f/0x650 kernel/sched/core.c:4921
 context_switch kernel/sched/core.c:5052 [inline]
 __schedule+0x11cb/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:next_tid mm/slub.c:2261 [inline]
RIP: 0010:slab_alloc_node mm/slub.c:3212 [inline]
RIP: 0010:slab_alloc mm/slub.c:3233 [inline]
RIP: 0010:kmem_cache_alloc+0x99/0x280 mm/slub.c:3238
Code: 3c 24 40 f6 c7 0f 0f 85 f9 01 00 00 48 8d 47 08 48 89 f9 48 83 c9 08 48 39 c1 0f 85 e7 01 00 00 41 8b 44 24 28 49 8b 5c 05 00 <48> 8d 4a 08 4c 89 e8 65 48 0f c7 0f 0f 94 c0 a8 01 75 60 eb 9b 31
RSP: 0018:ffffc9000323fe58 EFLAGS: 00000246
RAX: 0000000000000800 RBX: ffff8880504f3300 RCX: 00000000000414d8
RDX: 00000000003b3e30 RSI: 0000000000001000 RDI: 00000000000414d0
RBP: 0000000000000cc0 R08: ffffffff8d8b122f R09: 1ffffffff1b16245
R10: dffffc0000000000 R11: fffffbfff1b16246 R12: ffff888140006500
R13: ffff8880504f2200 R14: ffffffff81cb3867 R15: ffff888140006500
 getname_flags+0xb7/0x4f0 fs/namei.c:138
 getname fs/namei.c:217 [inline]
 __do_sys_mkdirat fs/namei.c:4156 [inline]
 __se_sys_mkdirat fs/namei.c:4154 [inline]
 __x64_sys_mkdirat+0x78/0x90 fs/namei.c:4154
 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: 0033:0x7f5ce37f3159
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:00007f5ce1a4b028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f5ce3a7afa0 RCX: 00007f5ce37f3159
RDX: 00000000000001ff RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f5ce388a03b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ce3a7b038 R14: 00007f5ce3a7afa0 R15: 00007ffcf8350028
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/12 05:54 linux-5.15.y 0996e0926f6b 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/09/11 16:41 linux-5.15.y 0996e0926f6b b6a5eeb7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_mkdirat
2026/07/29 10:10 linux-5.15.y 674f684f7c61 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/06/16 16:26 linux-5.15.y dc027a595035 a3998659 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/06/14 07:09 linux-5.15.y dc027a595035 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/05/15 03:10 linux-5.15.y de8dfb3f0278 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/05/03 14:15 linux-5.15.y ef251c45f1cd a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/04/11 06:58 linux-5.15.y 91d48252ad4b 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2026/01/09 12:00 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2025/12/31 19:52 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2025/12/25 19:32 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
2025/11/05 18:14 linux-5.15.y cc5ec8769306 a6c9c731 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdirat
* Struck through repros no longer work on HEAD.