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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: 205d, last: 15d
▶ ▼ Similar bugs (7)
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 554d 592d 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 934d 934d 0/3 auto-obsoleted due to no activity on 2024/02/15 18:20
upstream INFO: rcu detected stall in sys_mkdirat ext4 net 1 3 1144d 1260d 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 328d 529d 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 2 2d08h 28d 0/3 upstream: reported on 2026/05/01 18:50
linux-5.15 INFO: rcu detected stall in sys_mkdirat (2) 1 1 456d 456d 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 723d 775d 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=a0b/1/0x4000000000000000 softirq=10661/10662 fqs=5242 
	(detected by 1, t=10502 jiffies, g=13165, q=1223)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5760 Comm: syz.3.320 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:226 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x4/0x80 kernel/kcov.c:300
Code: 77 22 89 ff 89 f6 4a c7 44 02 08 05 00 00 00 4a 89 7c 02 10 4a 89 74 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 90 48 8b 04 24 <65> 48 8b 0d 44 37 89 7e 65 8b 15 45 37 89 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000007260 EFLAGS: 00000046
RAX: ffffffff81988349 RBX: ffff88805f2e6578 RCX: ffff888021d73b80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff88805f2e69eb R09: 1ffff1100be5cd3d
R10: dffffc0000000000 R11: ffffed100be5cd3e R12: ffff88805f2e6778
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff88805f2e6780
FS:  00007fe0b8af36c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f45ba620540 CR3: 000000001abc3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __perf_event_account_interrupt+0x179/0x280 kernel/events/core.c:9438
 __perf_event_overflow+0x99/0x530 kernel/events/core.c:9474
 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 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 32 e1 9c 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:ffffc900000077c0 EFLAGS: 00000206
RAX: 5ba7c2998d962300 RBX: 1ffff92000000efc RCX: 5ba7c2998d962300
RDX: dffffc0000000000 RSI: ffffffff8a2b2800 RDI: ffffffff8a79fe00
RBP: ffffc900000078a0 R08: ffffffff901d51c7 R09: 1ffffffff203aa38
R10: dffffc0000000000 R11: fffffbfff203aa39 R12: ffffffff8c323000
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]
 ndisc_send_skb+0xde0/0x1500 net/ipv6/ndisc.c:521
 addrconf_rs_timer+0x2d1/0x630 net/ipv6/addrconf.c:3956
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 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:preempt_latency_start kernel/sched/core.c:5492 [inline]
RIP: 0010:preempt_count_add+0xb5/0x190 kernel/sched/core.c:5515
Code: 0b 00 85 c0 74 09 31 db 31 ff e8 26 d1 0b 00 65 4c 8b 35 7e fe af 7e 49 81 c6 e8 14 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 81 e2 6b 00 49 89 1e 5b 41 5e 41 5f c3 89 fb e8
RSP: 0018:ffffc900035df588 EFLAGS: 00000246
RAX: 1ffff110043aea0d RBX: ffffffff81351d2c RCX: ffffffff962dbf00
RDX: dffffc0000000000 RSI: ffffffff89e000ca RDI: ffffffff81351d2c
RBP: ffffc900035df6b0 R08: ffffc900035df730 R09: 000000000000000a
R10: dffffc0000000000 R11: fffff520006bbed9 R12: ffffffff89e000ca
R13: ffffc900035dff58 R14: ffff888021d75068 R15: dffffc0000000000
 unwind_next_frame+0xac/0x1d90 arch/x86/kernel/unwind_orc.c:433
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 __memcg_init_list_lru_node mm/list_lru.c:339 [inline]
 memcg_update_list_lru_node mm/list_lru.c:396 [inline]
 memcg_update_list_lru mm/list_lru.c:473 [inline]
 memcg_update_all_list_lrus+0x2cc/0xba0 mm/list_lru.c:510
 memcg_alloc_cache_id mm/memcontrol.c:2964 [inline]
 memcg_online_kmem mm/memcontrol.c:3656 [inline]
 mem_cgroup_css_alloc+0xb25/0x1640 mm/memcontrol.c:5310
 css_create kernel/cgroup/cgroup.c:5389 [inline]
 cgroup_apply_control_enable+0x3cc/0xb00 kernel/cgroup/cgroup.c:3213
 cgroup_mkdir+0xcc0/0xec0 kernel/cgroup/cgroup.c:5609
 kernfs_iop_mkdir+0x24c/0x3d0 fs/kernfs/dir.c:1175
 vfs_mkdir+0x387/0x570 fs/namei.c:4073
 do_mkdirat+0x1df/0x5b0 fs/namei.c:4098
 __do_sys_mkdirat fs/namei.c:4113 [inline]
 __se_sys_mkdirat fs/namei.c:4111 [inline]
 __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4111
 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: 0033:0x7fe0ba899e59
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:00007fe0b8af3028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fe0bab12fa0 RCX: 00007fe0ba899e59
RDX: 00000000000001ff RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fe0ba92fd6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0bab13038 R14: 00007fe0bab12fa0 R15: 00007ffdce423cd8
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.