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INFO: rcu detected stall in sys_mkdir (2)

Status: upstream: reported on 2025/09/19 08:27
Reported-by: syzbot+6c3a319d0e21f2ddf26d@syzkaller.appspotmail.com
First crash: 10h27m, last: 10h27m
▶ ▼ Similar bugs (13)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sys_mkdir 1 1 266d 266d 0/3 auto-obsoleted due to no activity on 2025/04/06 10:37
linux-6.1 INFO: rcu detected stall in sys_mkdir 1 1 199d 199d 0/3 auto-obsoleted due to no activity on 2025/06/11 20:27
upstream INFO: rcu detected stall in sys_mkdir (3) cgroups 1 1 2081d 2081d 0/29 closed as invalid on 2020/01/08 05:33
upstream INFO: rcu detected stall in sys_mkdir (7) ext4 1 1 756d 756d 0/29 auto-obsoleted due to no activity on 2023/10/24 07:40
linux-6.6 INFO: rcu detected stall in sys_mkdir 1 1 31d 31d 0/2 upstream: reported on 2025/08/19 00:13
upstream INFO: rcu detected stall in sys_mkdir mm 1 2 2249d 2251d 0/29 auto-closed as invalid on 2019/10/25 14:21
upstream INFO: rcu detected stall in sys_mkdir (2) cgroups 1 5 2116d 2117d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in sys_mkdir (6) ext4 1 2 1328d 1336d 0/29 closed as invalid on 2022/02/08 09:50
upstream INFO: rcu detected stall in sys_mkdir (4) mm 1 2 2081d 2081d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in sys_mkdir (9) ext4 mm 1 syz done 3 30d 237d 0/29 upstream: reported syz repro on 2025/01/25 04:35
upstream INFO: rcu detected stall in sys_mkdir (8) fs 1 1 355d 355d 0/29 auto-obsoleted due to no activity on 2024/12/28 09:04
upstream INFO: rcu detected stall in sys_mkdir (5) tomoyo 1 1 1463d 1463d 0/29 auto-closed as invalid on 2021/12/15 23:48
android-5-15 BUG: soft lockup in sys_mkdir 1 2 490d 494d 0/2 auto-obsoleted due to no activity on 2024/08/15 15:43

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 ticks this GP) idle=295/1/0x4000000000000002 softirq=7495/7495 fqs=2099 
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4614
	(detected by 1, t=10502 jiffies, g=8997, q=512)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4614 Comm: syz.1.95 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:kasan_check_range+0x1ab/0x290 mm/kasan/generic.c:-1
Code: 4d 89 d6 4d 8d 56 07 4d 85 f6 4d 0f 49 d6 49 83 e2 f8 4d 29 d6 74 12 41 80 39 00 0f 85 a0 00 00 00 49 ff c1 49 ff ce 75 ee 5b <41> 5e 41 5f c3 84 db 75 61 f7 c3 00 ff 00 00 75 5e f7 c3 00 00 ff
RSP: 0018:ffffc90000006b28 EFLAGS: 00000056
RAX: 0000000000000001 RBX: 0000000000000002 RCX: ffffffff815c0676
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbc0d8
RBP: ffffc90000006d90 R08: dffffc0000000000 R09: fffffbfff1ff781c
R10: fffffbfff1ff781c R11: 1ffffffff1ff781b R12: ffff88802b9ec6e0
R13: ffff88802b9ec602 R14: 0000000000000001 R15: dffffc0000000001
FS:  00007f3c78b066c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3c78ae5d58 CR3: 00000000744cd000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 hlock_class kernel/locking/lockdep.c:197 [inline]
 check_wait_context kernel/locking/lockdep.c:4711 [inline]
 __lock_acquire+0x916/0x7c60 kernel/locking/lockdep.c:4962
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0x97/0xa30 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7804 [inline]
 perf_event_output_forward+0x15c/0x280 kernel/events/core.c:7822
 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
 perf_tp_event+0x32c/0xb50 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 perf_trace_preemptirq_template+0x2be/0x380 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:unwind_next_frame+0xbc/0x1d90 arch/x86/kernel/unwind_orc.c:436
Code: ac 24 80 00 00 00 4c 89 64 24 58 4c 89 7c 24 48 bf 01 00 00 00 e8 44 f7 1c 00 4c 8d 7b 50 4c 89 f8 48 c1 e8 03 48 89 44 24 30 <42> 80 3c 30 00 74 08 4c 89 ff e8 05 ba 87 00 4c 89 7c 24 28 4d 8b
RSP: 0018:ffffc900000076a8 EFLAGS: 00000a02
RAX: 1ffff92000000ef7 RBX: ffffc90000007768 RCX: ffffffff960c2f03
RDX: dffffc0000000000 RSI: ffffffff81c9b52c RDI: 0000000000000001
RBP: ffffc900000077b0 R08: ffffc90000007830 R09: 0000000000000013
R10: fffff52000000ef9 R11: 1ffff92000000ef7 R12: ffffffff81c9b52c
R13: ffffc9000382fd58 R14: dffffc0000000000 R15: ffffc900000077b8
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 rcu_do_batch kernel/rcu/tree.c:2523 [inline]
 rcu_core+0x962/0x15d0 kernel/rcu/tree.c:2763
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x12f/0x220 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:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:674
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 ad 13 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc9000382f6a0 EFLAGS: 00000206
RAX: 18f10f4f185add00 RBX: 1ffff92000705ed8 RCX: 18f10f4f185add00
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a480
RBP: ffffc9000382f778 R08: dffffc0000000000 R09: fffffbfff1ff782c
R10: fffffbfff1ff782c R11: 1ffffffff1ff782b R12: ffffffff8c120b01
R13: dffffc0000000000 R14: 0000000000000246 R15: ffff88802b9ebb80
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:771 [inline]
 d_alloc_parallel+0x104f/0x12d0 fs/dcache.c:2671
 __lookup_slow+0x113/0x3d0 fs/namei.c:1648
 lookup_slow+0x53/0x70 fs/namei.c:1680
 walk_component+0x319/0x460 fs/namei.c:1976
 link_path_walk+0x662/0xd40 fs/namei.c:-1
 path_parentat fs/namei.c:2502 [inline]
 __filename_parentat+0x1f3/0x5f0 fs/namei.c:2526
 filename_parentat fs/namei.c:2544 [inline]
 filename_create+0xcc/0x450 fs/namei.c:3816
 do_mkdirat+0x9d/0x5a0 fs/namei.c:4080
 __do_sys_mkdir fs/namei.c:4110 [inline]
 __se_sys_mkdir fs/namei.c:4108 [inline]
 __x64_sys_mkdir+0x6a/0x80 fs/namei.c:4108
 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: 0033:0x7f3c7a89eba9
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:00007f3c78b06038 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
RAX: ffffffffffffffda RBX: 00007f3c7aae5fa0 RCX: 00007f3c7a89eba9
RDX: 0000000000000000 RSI: 000000000000008c RDI: 0000200000000040
RBP: 00007f3c7a921e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3c7aae6038 R14: 00007f3c7aae5fa0 R15: 00007fffb5a0fe98
 </TASK>
task:syz.1.95        state:R  running task     stack:25440 pid: 4614 ppid:  4189 flags:0x0000400c
Call Trace:
 <TASK>
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/19 08:26 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_mkdir
* Struck through repros no longer work on HEAD.