syzbot

 sign-in | mailing list | source | docs
🐞 Open [907]
🐞 Fixed [143]
🐞 Invalid [1097]
⬇ Missing Backports [73]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: rcu detected stall in sys_mkdirat

Status: auto-obsoleted due to no activity on 2025/03/02 02:09
Reported-by: syzbot+005a4e31cafef8f9177a@syzkaller.appspotmail.com
First crash: 573d, last: 534d
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sys_mkdirat 1 1 914d 914d 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 1124d 1240d 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 308d 509d 0/29 auto-obsoleted due to no activity on 2025/10/13 21:11
linux-5.15 INFO: rcu detected stall in sys_mkdirat (3) 1 6 7d00h 185d 0/3 upstream: reported on 2025/11/05 18:14
linux-6.1 INFO: rcu detected stall in sys_mkdirat (2) 1 1 8d20h 8d20h 0/3 upstream: reported on 2026/05/01 18:50
linux-5.15 INFO: rcu detected stall in sys_mkdirat (2) 1 1 436d 436d 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 703d 755d 0/2 auto-obsoleted due to no activity on 2024/09/03 20:00

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 0-.... } 2826 jiffies s: 5417 root: 0x1/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4863 Comm: syz.3.119 Not tainted 6.1.118-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:strlen+0x3f/0x60 lib/string.c:495
Code: 00 00 00 fc ff df 48 89 fb 49 89 c4 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 12 48 ff c3 49 8d 44 24 01 43 80 7c 26 01 00 <75> dd eb 13 89 d9 80 e1 07 38 c1 7c e5 48 89 df e8 5c 95 40 f7 eb
RSP: 0018:ffffc90000006cb8 EFLAGS: 00000006
RAX: 0000000000000004 RBX: ffffffff8b0d1565 RCX: 0000000000006d03
RDX: ffffffff813dce1f RSI: ffffffff8d32aec0 RDI: ffffffff8b0d1560
RBP: ffffc90000006df0 R08: dffffc0000000000 R09: fffffbfff1d3415e
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000003
R13: ffffffff813dce1f R14: ffffffff8b0d1560 R15: dffffc0000000000
FS:  00007f547f7596c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2f26fe30f0 CR3: 000000002f6a5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 trace_event_get_offsets_lock include/trace/events/lock.h:50 [inline]
 perf_trace_lock+0x10c/0x440 include/trace/events/lock.h:50
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x995/0xa20 kernel/locking/lockdep.c:5673
 rcu_lock_release include/linux/rcupdate.h:355 [inline]
 rcu_read_unlock_sched include/linux/rcupdate.h:904 [inline]
 pfn_valid include/linux/mmzone.h:1867 [inline]
 __virt_addr_valid+0x42b/0x530 arch/x86/mm/physaddr.c:65
 kasan_addr_to_slab+0x9/0x20 mm/kasan/common.c:35
 __kasan_record_aux_stack+0x11/0xc0 mm/kasan/generic.c:471
 irq_work_queue_on+0x12f/0x290 kernel/irq_work.c:140
 rcu_read_unlock_special+0x3c6/0x540 kernel/rcu/tree_plugin.h:675
 __rcu_read_unlock+0x92/0x100 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 __perf_event_output kernel/events/core.c:7717 [inline]
 perf_event_output_forward+0x2af/0x330 kernel/events/core.c:7726
 __perf_event_overflow+0x45e/0x640 kernel/events/core.c:9472
 perf_tp_event+0x35a/0xc80 kernel/events/core.c:10005
 perf_trace_run_bpf_submit+0xf7/0x1d0 kernel/events/core.c:9978
 perf_trace_preemptirq_template+0x2d1/0x3d0 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0xd5/0x140 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x84/0x540 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 49 89 04 17 66 41 c7 44 17 09 f3 f3 41 c6 44 17 0b f3 65 44 8b 25 7d 28 8e 7e 41 f7 c4 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 3a 00 00 00 00 66 42 c7 44 3a
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: fd363f16dc6cae00 RBX: 1ffff92000000ef8 RCX: ffffffff816b024a
RDX: dffffc0000000000 RSI: ffffffff8b0c01c0 RDI: ffffffff8b5d7800
RBP: ffffc90000007858 R08: dffffc0000000000 R09: fffffbfff224626a
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff8d32fe00
R13: ffff88807ddf8458 R14: ffffc900000077c0 R15: 1ffff92000000ef4
 __rcu_read_unlock+0x92/0x100 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 ndisc_send_skb+0xd68/0x14e0 net/ipv6/ndisc.c:519
 addrconf_rs_timer+0x357/0x610 net/ipv6/addrconf.c:3963
 call_timer_fn+0x1ad/0x6b0 kernel/time/timer.c:1504
 expire_timers kernel/time/timer.c:1549 [inline]
 __run_timers+0x67c/0x890 kernel/time/timer.c:1820
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1833
 handle_softirqs+0x2ee/0xa40 kernel/softirq.c:571
 __do_softirq kernel/softirq.c:605 [inline]
 invoke_softirq kernel/softirq.c:445 [inline]
 __irq_exit_rcu+0x157/0x240 kernel/softirq.c:654
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:666
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 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:finish_task_switch+0x1d3/0x810 kernel/sched/core.c:5120
Code: 38 0b 00 48 83 c4 08 4c 89 f7 e8 68 31 00 00 0f 1f 44 00 00 4c 89 f7 e8 4b 7d 52 09 e8 66 f3 31 00 fb 49 8d bc 24 f8 15 00 00 <48> 89 f8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28
RSP: 0018:ffffc900051f6f08 EFLAGS: 00000286
RAX: fd363f16dc6cae00 RBX: ffff88802cf6d974 RCX: ffffffff816b024a
RDX: dffffc0000000000 RSI: ffffffff8b0c01c0 RDI: ffff88807ddf95f8
RBP: ffffc900051f6f50 R08: dffffc0000000000 R09: fffffbfff224624d
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807ddf8000
R13: 1ffff110171c76e3 R14: ffff8880b8e3a9c0 R15: ffff8880b8e3b718
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x1447/0x4570 kernel/sched/core.c:6558
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6727
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6751
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 unwind_next_frame+0x1a55/0x2220 arch/x86/kernel/unwind_orc.c:629
 arch_stack_walk+0x10d/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 save_stack+0xf6/0x1e0 mm/page_owner.c:127
 __set_page_owner+0x26/0x390 mm/page_owner.c:190
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2517
 prep_new_page mm/page_alloc.c:2524 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4313
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5589
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc+0xa1/0x230 mm/slab_common.c:949
 kmalloc include/linux/slab.h:562 [inline]
 kzalloc include/linux/slab.h:693 [inline]
 cgroup_create kernel/cgroup/cgroup.c:5601 [inline]
 cgroup_mkdir+0x449/0xff0 kernel/cgroup/cgroup.c:5747
 kernfs_iop_mkdir+0x275/0x400 fs/kernfs/dir.c:1221
 vfs_mkdir+0x3b6/0x590 fs/namei.c:4106
 do_mkdirat+0x225/0x360 fs/namei.c:4131
 __do_sys_mkdirat fs/namei.c:4146 [inline]
 __se_sys_mkdirat fs/namei.c:4144 [inline]
 __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4144
 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: 0033:0x7f547e97e819
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f547f759038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007f547eb35fa0 RCX: 00007f547e97e819
RDX: 00000000000001ff RSI: 0000000020000000 RDI: ffffffffffffff9c
RBP: 00007f547e9f175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f547eb35fa0 R15: 00007ffff6de7548
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/22 02:08 linux-6.1.y b67dc5c9ade9 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_mkdirat
2024/10/14 13:32 linux-6.1.y aa4cd140bba5 084d8178 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_mkdirat
* Struck through repros no longer work on HEAD.