INFO: rcu detected stall in clone3 (3)

Status: upstream: reported syz repro on 2026/07/10 04:09
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+d2f8d9990c9a9fb93118@syzkaller.appspotmail.com
First crash: 100d, last: 19d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/10/10 linux-5.15.y (ToT) a051a4bf909f syz [report] INFO: rcu detected stall in corrupted
2026/10/10 upstream (ToT) 3857c2fe5449 syz Didn't crash
▶ ▼ Similar bugs (20)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in clone3 origin:lts-only 1 syz, C inconclusive 2 317d 381d 0/2 upstream: reported C repro on 2025/10/02 07:48
upstream INFO: rcu detected stall in clone3 (5) mm 1 7 657d 867d 0/29 auto-obsoleted due to no activity on 2025/03/30 08:38
upstream INFO: rcu detected stall in clone3 mm 1 2 1740d 1766d 0/29 closed as invalid on 2022/02/08 10:10
linux-5.15 INFO: rcu detected stall in clone3 (2) 1 1 231d 231d 0/3 auto-obsoleted due to no activity on 2026/06/09 00:21
linux-5.15 INFO: rcu detected stall in clone3 1 2 438d 473d 0/3 auto-obsoleted due to no activity on 2025/11/14 02:35
upstream INFO: rcu detected stall in clone3 (2) kernfs 1 1 1588d 1588d 0/29 auto-closed as invalid on 2022/09/10 23:49
upstream INFO: rcu detected stall in clone3 (3) kernel 1 1 1337d 1337d 0/29 auto-obsoleted due to no activity on 2023/05/19 23:49
upstream INFO: rcu detected stall in clone3 (4) mm net 1 2 1151d 1230d 0/29 auto-obsoleted due to no activity on 2023/11/22 09:08
upstream INFO: rcu detected stall in clone3 (6) prio:high mm 1 63 17h13m 143d 0/29 upstream: reported on 2026/05/28 01:12
upstream INFO: rcu detected stall in sys_clone3 (3) mm 1 26 581d 776d 0/29 auto-obsoleted due to no activity on 2025/06/14 09:25
linux-6.1 INFO: rcu detected stall in sys_clone3 (3) 1 3 695d 754d 0/3 auto-obsoleted due to no activity on 2025/03/02 13:35
upstream INFO: rcu detected stall in sys_clone3 kernfs 1 1 1610d 1610d 0/29 auto-closed as invalid on 2022/08/20 13:01
linux-5.15 INFO: rcu detected stall in sys_clone3 1 1 744d 744d 0/3 auto-obsoleted due to no activity on 2025/01/12 11:21
upstream INFO: rcu detected stall in sys_clone3 (2) mm 1 3 874d 978d 0/29 auto-obsoleted due to no activity on 2024/08/25 02:20
linux-6.1 INFO: rcu detected stall in sys_clone3 1 1 1016d 1012d 0/3 auto-obsoleted due to no activity on 2024/04/15 06:45
linux-6.1 INFO: rcu detected stall in sys_clone3 (4) 1 1 556d 556d 0/3 auto-obsoleted due to no activity on 2025/07/18 19:29
linux-5.15 INFO: rcu detected stall in sys_clone3 (2) 1 1 611d 611d 0/3 auto-obsoleted due to no activity on 2025/05/25 09:12
linux-6.1 INFO: rcu detected stall in sys_clone3 (2) 1 1 876d 876d 0/3 auto-obsoleted due to no activity on 2024/09/01 21:33
android-5-10 BUG: soft lockup in sys_clone3 1 1 284d 284d 0/2 auto-obsoleted due to no activity on 2026/04/07 17:52
android-5-10 BUG: soft lockup in sys_clone3 (2) 1 1 23h12m 23h11m 0/2 premoderation: reported on 2026/10/17 19:03

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-....: (0 ticks this GP) idle=139/1/0x4000000000000002 softirq=22392/22392 fqs=2100 
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4376/1:b..l
	(detected by 1, t=10506 jiffies, g=37049, q=252911)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12275 Comm: syz.4.2956 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:201
Code: 2e 0f 1f 84 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 80 0c 12 0c 48 89 de 5b e9 47 6b 44 00 00 00 cc cc 00 00 cc <48> 8b 04 24 65 48 8b 0d 14 5b 89 7e 65 8b 15 15 5b 89 7e 81 e2 00
RSP: 0018:ffffc90000007a10 EFLAGS: 00000046
RAX: ffffffff817f418b RBX: 0000000000000000 RCX: ffff88802c35bb80
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8d8b1eef R09: 1ffffffff1b163dd
R10: dffffc0000000000 R11: fffffbfff1b163de R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff89e00e46 R15: 0000000000000000
FS:  0000555571bfd500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8a892b9d58 CR3: 000000005a6b4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 trace_irq_enable_rcuidle+0xac/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 42 0b 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:ffffc90000007b00 EFLAGS: 00000206
RAX: 5cc91ea17751aa00 RBX: 1ffff92000000f64 RCX: 5cc91ea17751aa00
RDX: dffffc0000000000 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffc90000007bd8 R08: ffffffff901f10d7 R09: 1ffffffff203e21a
R10: dffffc0000000000 R11: fffffbfff203e21b 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]
 ieee80211_iterate_active_interfaces_atomic+0x132/0x140 net/mac80211/util.c:831
 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4ea/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1766
 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:seqcount_lockdep_reader_access+0x196/0x1d0 include/linux/seqlock.h:106
Code: 00 4d 85 e4 75 16 e8 29 08 10 00 eb 15 e8 22 08 10 00 e8 6d 28 58 08 4d 85 e4 74 ea e8 13 08 10 00 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900050378e0 EFLAGS: 00000293
RAX: ffffffff81690c8d RBX: 0000000000000000 RCX: ffff88802c35bb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90005037998 R08: ffffffff901f10d7 R09: 1ffffffff203e21a
R10: dffffc0000000000 R11: fffffbfff203e21b R12: 0000000000000200
R13: dffffc0000000000 R14: 1ffff92000a06f1c R15: dffffc0000000000
 timekeeping_get_delta kernel/time/timekeeping.c:254 [inline]
 timekeeping_get_ns kernel/time/timekeeping.c:388 [inline]
 ktime_get_with_offset+0xff/0x320 kernel/time/timekeeping.c:874
 ktime_get_boottime include/linux/timekeeping.h:95 [inline]
 ktime_get_boottime_ns include/linux/timekeeping.h:164 [inline]
 copy_process+0x2335/0x3e70 kernel/fork.c:2409
 kernel_clone+0x23f/0x990 kernel/fork.c:2682
 __do_sys_clone3 kernel/fork.c:2957 [inline]
 __se_sys_clone3+0x312/0x3d0 kernel/fork.c:2941
 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: 0033:0x7f8a89c7af49
Code: 90 b8 01 00 00 00 b9 01 00 00 00 eb ec 0f 1f 40 00 b8 ea ff ff ff 48 85 ff 74 28 48 85 d2 74 23 49 89 c8 b8 b3 01 00 00 0f 05 <48> 85 c0 7c 14 74 01 c3 31 ed 4c 89 c7 ff d2 48 89 c7 b8 3c 00 00
RSP: 002b:00007ffffa18d7b8 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f8a89c364e0 RCX: 00007f8a89c7af49
RDX: 00007f8a89c364e0 RSI: 0000000000000058 RDI: 00007ffffa18d810
RBP: 00007f8a892b96c0 R08: 00007f8a892b96c0 R09: 00007ffffa18d8f7
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffe8
R13: 000000000000006e R14: 00007ffffa18d810 R15: 00007ffffa18d8f8
 </TASK>
task:kworker/0:31    state:R  running task     stack:23568 pid: 4376 ppid:     2 flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:435
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:seqcount_lockdep_reader_access+0x196/0x1d0 include/linux/seqlock.h:106
Code: f9 4d 85 e4 75 16 e8 e9 98 50 f9 eb 15 e8 e2 98 50 f9 e8 2d b9 98 01 4d 85 e4 74 ea e8 d3 98 50 f9 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 43 c7 44 3e 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900035efa20 EFLAGS: 00000293
RAX: ffffffff88287bcd RBX: 0000000000000000 RCX: ffff88802a649dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900035efad0 R08: ffffffff901f115f R09: 1ffffffff203e22b
R10: dffffc0000000000 R11: fffffbfff203e22c R12: 0000000000000200
R13: dffffc0000000000 R14: 1ffff920006bdf44 R15: dffffc0000000000
 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:338 [inline]
 gc_worker+0x2e5/0x13d0 net/netfilter/nf_conntrack_core.c:1486
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/29 11:44 linux-5.15.y 0248c33e835e 7bf4ea23 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in clone3
2026/07/10 04:08 linux-5.15.y c86c4726e7f0 4167ee25 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in clone3
* Struck through repros no longer work on HEAD.