INFO: rcu detected stall in dput (3)

Status: upstream: reported syz repro on 2024/12/09 17:03
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+593324eabd9eef11e831@syzkaller.appspotmail.com
First crash: 594d, last: 192d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/11/19 linux-5.15.y (ToT) cc5ec8769306 syz [report] INFO: rcu detected stall in corrupted
2025/11/19 upstream (ToT) 8b690556d8fe syz Didn't crash
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in dput (2) origin:lts-only 1 C error 54 198d 789d 0/3 upstream: reported C repro on 2024/05/28 13:43
upstream INFO: rcu detected stall in dput (4) kvm 1 C error error 2 1689d 2049d 0/29 closed as invalid on 2022/02/08 10:37
upstream INFO: rcu detected stall in dput (3) mm 1 1 2391d 2391d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in dput (8) prio:low fs 1 C done error 635 190d 938d 0/29 upstream: reported C repro on 2023/12/31 19:35
linux-5.15 INFO: rcu detected stall in dput 1 2 1062d 1102d 0/3 auto-obsoleted due to no activity on 2023/12/08 00:28
upstream INFO: rcu detected stall in dput (6) fs 1 2 1363d 1422d 0/29 auto-obsoleted due to no activity on 2023/01/16 04:13
linux-5.15 INFO: rcu detected stall in dput (2) 1 10 721d 863d 0/3 auto-obsoleted due to no activity on 2024/11/12 09:55
upstream INFO: rcu detected stall in dput (5) fs 1 1 1559d 1559d 0/29 auto-closed as invalid on 2022/07/18 12:41
linux-6.1 INFO: rcu detected stall in dput 1 1 1110d 1110d 0/3 auto-obsoleted due to no activity on 2023/10/20 22:44
upstream INFO: rcu detected stall in dput fs 1 1 2427d 2426d 0/29 closed as invalid on 2019/12/04 14:04
linux-6.6 INFO: rcu detected stall in dput 1 44 192d 404d 0/2 auto-obsoleted due to no activity on 2026/03/27 04:02
upstream INFO: rcu detected stall in dput (2) mm 1 2 2391d 2391d 0/29 closed as invalid on 2020/01/08 05:33
▶ ▼ Last patch testing requests (6)
Created Duration User Patch Repo Result
2026/06/23 20:26 19m retest repro linux-5.15.y report log
2026/06/23 20:26 20m retest repro linux-5.15.y report log
2026/04/09 09:29 20m retest repro linux-5.15.y report log
2026/04/09 09:29 14m retest repro linux-5.15.y report log
2026/01/29 08:52 22m retest repro linux-5.15.y report log
2026/01/29 08:52 15m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2026/06/01 12:36 16m fix candidate upstream error job log
2026/03/28 03:50 1m fix candidate upstream error job log
2026/02/24 06:47 1m fix candidate upstream error job log
2026/01/24 20:22 1m fix candidate upstream error job log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (1 GPs behind) idle=b31/1/0x4000000000000002 softirq=6989/6992 fqs=5161 
	(detected by 1, t=10502 jiffies, g=6805, q=254108)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4424 Comm: syz.3.37 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:313
Code: c1 03 38 c1 0f 8c 0d ff ff ff 4c 89 ff e8 a3 d2 21 00 e9 00 ff ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 e8 fb 69 dd ff <e8> f6 69 dd ff 48 c7 c7 20 c7 11 8c 31 f6 31 d2 b9 02 00 00 00 45
RSP: 0018:ffffc90000006f98 EFLAGS: 00000046
RAX: ffffffff819a6215 RBX: ffff88807bf28000 RCX: ffff8880225e8000
RDX: 0000000000000100 RSI: ffffc90000007340 RDI: ffffc90000007120
RBP: ffffc900000070d0 R08: dffffc0000000000 R09: ffffc90000007120
R10: fffff52000000e2b R11: 1ffff92000000e24 R12: 1ffff92000000e04
R13: 0000000000000008 R14: ffffc90000007120 R15: ffffc90000007340
FS:  0000555572a64500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32b63fff CR3: 000000007394a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_read_lock include/linux/rcupdate.h:740 [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_swevent_overflow kernel/events/core.c:9591 [inline]
 perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
 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: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 ed 11 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:ffffc900000077a0 EFLAGS: 00000206
RAX: 8bb43a1f43347900 RBX: 1ffff92000000ef8 RCX: 8bb43a1f43347900
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: ffffffff8a59e800
RBP: ffffc90000007880 R08: dffffc0000000000 R09: fffffbfff1ff543d
R10: fffffbfff1ff543d R11: 1ffffffff1ff543c R12: ffffffff8c120c00
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+0xdc4/0x14a0 net/ipv6/ndisc.c:521
 addrconf_rs_timer+0x2b8/0x600 net/ipv6/addrconf.c:3956
 call_timer_fn+0x16c/0x530 kernel/time/timer.c:1451
 expire_timers kernel/time/timer.c:1496 [inline]
 __run_timers+0x525/0x7c0 kernel/time/timer.c:1767
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 be 9a d2 f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> d6 22 a6 f7 65 8b 05 67 20 57 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc9000380fb60 EFLAGS: 00000206
RAX: 8bb43a1f43347900 RBX: 0000000000000a06 RCX: 8bb43a1f43347900
RDX: dffffc0000000000 RSI: ffffffff8a0b1be0 RDI: 0000000000000001
RBP: ffffc9000380fbf8 R08: dffffc0000000000 R09: ffffed1017207662
R10: ffffed1017207662 R11: 1ffff11017207661 R12: dffffc0000000000
R13: ffff88805758c758 R14: ffffffff962d3b60 R15: 1ffff92000701f6c
 __debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
 debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
 slab_free_hook mm/slub.c:1685 [inline]
 slab_free_freelist_hook+0x8b/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 __dentry_kill+0x4ef/0x650 fs/dcache.c:600
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xd8/0x1a0 fs/dcache.c:893
 __fput+0x5ee/0x930 fs/file_table.c:319
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f7522add749
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:00007ffcb63bb868 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 000000000002deaa RCX: 00007f7522add749
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 00000001b63bbb5f
R10: 0000001b31f20000 R11: 0000000000000246 R12: 00007f7522d33fac
R13: 00007f7522d33fa0 R14: ffffffffffffffff R15: 0000000000000005
 </TASK>

Crashes (25):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/08 16:21 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dput
2025/11/19 09:54 linux-5.15.y cc5ec8769306 ef766cd7 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dput
2026/01/15 07:05 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 dput
2026/01/14 09:53 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/12/11 11:18 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 dput
2025/12/04 12:22 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/11/19 07:33 linux-5.15.y cc5ec8769306 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dput
2025/11/02 13:01 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/10/18 02:57 linux-5.15.y 29e53a5b1c4f 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/09/16 13:32 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/08/26 12:03 linux-5.15.y c79648372d02 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in dput
2025/07/21 00:15 linux-5.15.y c79648372d02 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/06/20 09:46 linux-5.15.y 1c700860e8bc ed3e87f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/06/12 12:34 linux-5.15.y 1c700860e8bc 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/06/06 16:46 linux-5.15.y 1c700860e8bc 9fa58bba .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/05/30 12:06 linux-5.15.y 98f47d0e9b8c 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/03/31 09:50 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/03/12 05:52 linux-5.15.y c16c81c81336 ee70e6db .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/03/04 13:02 linux-5.15.y c16c81c81336 c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/01/03 21:59 linux-5.15.y 91786f140358 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/01/01 15:22 linux-5.15.y 91786f140358 d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2024/12/12 19:52 linux-5.15.y 0a51d2d4527b 530e80f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2024/12/09 17:02 linux-5.15.y 0a51d2d4527b 9ac0fdc6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in dput
2025/06/25 13:59 linux-5.15.y 1c700860e8bc 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in dput
2025/06/04 06:25 linux-5.15.y 98f47d0e9b8c a30356b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: soft lockup in dput
* Struck through repros no longer work on HEAD.