INFO: rcu detected stall in sys_clone (2)

Status: upstream: reported on 2025/12/09 09:13
Reported-by: syzbot+7919861b650883ef99d9@syzkaller.appspotmail.com
First crash: 290d, last: 20d
▶ ▼ Similar bugs (19)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in sys_clone 1 syz, C done 8 325d 409d 2/2 fixed on 2025/12/06 23:11
linux-5.15 INFO: rcu detected stall in sys_clone 1 1 1024d 1024d 0/3 auto-obsoleted due to no activity on 2024/03/15 18:08
linux-6.1 INFO: rcu detected stall in sys_clone 1 3 1171d 1243d 0/3 auto-obsoleted due to no activity on 2023/10/20 18:18
upstream INFO: rcu detected stall in sys_clone (2) mm 1 49 2397d 2514d 0/29 auto-closed as invalid on 2020/06/01 05:26
upstream INFO: rcu detected stall in sys_clone (4) kernel 1 1 1914d 1914d 0/29 auto-closed as invalid on 2021/09/27 17:49
upstream INFO: rcu detected stall in sys_clone (3) mm 1 2 2250d 2272d 0/29 auto-closed as invalid on 2020/10/26 22:48
upstream INFO: rcu detected stall in sys_clone (6) kasan mm 1 1 1585d 1585d 0/29 auto-closed as invalid on 2022/08/23 03:28
upstream INFO: rcu detected stall in sys_clone kernel 1 1 2570d 2570d 13/29 fixed on 2019/10/09 10:54
upstream INFO: rcu detected stall in sys_clone (8) mm 1 syz, C error 504 2d08h 911d 0/29 upstream: reported C repro on 2024/03/29 00:16
linux-4.19 INFO: rcu detected stall in sys_clone 1 2 2468d 2487d 0/1 auto-closed as invalid on 2020/04/21 05:46
upstream INFO: rcu detected stall in sys_clone (5) kernfs 1 5 1719d 1818d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in sys_clone (7) fs 1 1 1320d 1320d 0/29 auto-obsoleted due to no activity on 2023/05/14 17:18
linux-5.15 INFO: rcu detected stall in sys_clone (2) missing-backport origin:upstream 1 syz, C done 203 4d02h 913d 0/3 upstream: reported C repro on 2024/03/27 00:16
linux-6.1 INFO: rcu detected stall in sys_clone (2) origin:upstream missing-backport 1 syz, C error 123 3d15h 919d 0/3 upstream: reported C repro on 2024/03/20 15:17
android-5-10 BUG: soft lockup in sys_clone 1 1 809d 809d 0/2 auto-obsoleted due to no activity on 2024/10/06 12:58
android-5-10 BUG: soft lockup in sys_clone (2) 1 1 384d 384d 0/2 auto-obsoleted due to no activity on 2025/12/06 02:03
android-5-10 BUG: soft lockup in sys_clone (4) 1 1 110d 110d 0/2 auto-obsoleted due to no activity on 2026/09/05 05:34
android-5-10 BUG: soft lockup in sys_clone (3) 1 1 236d 236d 0/2 auto-obsoleted due to no activity on 2026/05/02 19:39
android-5-15 BUG: soft lockup in sys_clone origin:upstream 1 syz, C error 18 745d 889d 0/2 auto-obsoleted due to no activity on 2024/12/19 12:14

Sample crash report:
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=3494/1/0x4000000000000000 softirq=25197/25198 fqs=5238
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1197535          0            0
rcu: 	cputime:    18375      34104           73   ==> 52500(ms)
rcu: 	(t=10502 jiffies g=34481 q=3215 ncpus=2)
CPU: 0 PID: 8608 Comm: syz.2.765 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:seqcount_lockdep_reader_access+0x19a/0x1d0 include/linux/seqlock.h:105
Code: 00 4d 85 e4 75 16 e8 05 ca 0f 00 eb 15 e8 fe c9 0f 00 e8 09 12 18 09 4d 85 e4 74 ea e8 ef c9 0f 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:ffffc900000068c0 EFLAGS: 00000246
RAX: ffffffff8177b881 RBX: 0000000000000000 RCX: ffff888022978000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000006978 R08: ffffffff911ef5f7 R09: 1ffffffff223debe
R10: dffffc0000000000 R11: fffffbfff223debf R12: 0000000000000200
R13: 000001fb63109b96 R14: 1ffff92000000d18 R15: dffffc0000000000
FS:  00007f54f08976c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f74ba2e3e9c CR3: 000000005e97d000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 ktime_get_with_offset+0x94/0x330 kernel/time/timekeeping.c:889
 ktime_get_real include/linux/timekeeping.h:79 [inline]
 netif_rx_internal+0x33d/0x4e0 net/core/dev.c:5177
 __netif_rx+0x78/0xc0 net/core/dev.c:5220
 veth_forward_skb drivers/net/veth.c:325 [inline]
 veth_xmit+0x57a/0xa30 drivers/net/veth.c:378
 __netdev_start_xmit include/linux/netdevice.h:4982 [inline]
 netdev_start_xmit include/linux/netdevice.h:4996 [inline]
 xmit_one net/core/dev.c:3649 [inline]
 dev_hard_start_xmit+0x269/0x790 net/core/dev.c:3665
 __dev_queue_xmit+0x1be8/0x37e0 net/core/dev.c:4478
 dev_queue_xmit include/linux/netdevice.h:3157 [inline]
 br_dev_queue_push_xmit+0x6b7/0x880 net/bridge/br_forward.c:53
 NF_HOOK+0x351/0x3e0 include/linux/netfilter.h:304
 br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
 NF_HOOK+0x351/0x3e0 include/linux/netfilter.h:304
 __br_forward+0x433/0x610 net/bridge/br_forward.c:115
 br_dev_xmit+0x10f3/0x18a0 net/bridge/br_device.c:-1
 __netdev_start_xmit include/linux/netdevice.h:4982 [inline]
 netdev_start_xmit include/linux/netdevice.h:4996 [inline]
 xmit_one net/core/dev.c:3649 [inline]
 dev_hard_start_xmit+0x269/0x790 net/core/dev.c:3665
 __dev_queue_xmit+0x1be8/0x37e0 net/core/dev.c:4478
 neigh_output include/net/neighbour.h:547 [inline]
 ip6_finish_output2+0xf7a/0x1690 net/ipv6/ip6_output.c:143
 dst_output include/net/dst.h:467 [inline]
 NF_HOOK include/linux/netfilter.h:304 [inline]
 ndisc_send_skb+0xbb9/0x1480 net/ipv6/ndisc.c:513
 addrconf_rs_timer+0x36b/0x640 net/ipv6/addrconf.c:4036
 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701
 expire_timers kernel/time/timer.c:1752 [inline]
 __run_timers+0x570/0x810 kernel/time/timer.c:2023
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036
 handle_softirqs+0x27d/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:finish_task_switch+0x267/0x8f0 kernel/sched/core.c:5256
Code: 31 09 85 c0 0f 84 30 01 00 00 48 85 db 0f 85 4f 01 00 00 0f 1f 44 00 00 4c 89 e7 e8 a3 a7 3b 09 e8 4e 1a 30 00 fb 4c 8b 65 b8 <49> 8d bc 24 00 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0
RSP: 0018:ffffc9000bd471a0 EFLAGS: 00000286
RAX: 14fbc9697148f000 RBX: 0000000000000000 RCX: 14fbc9697148f000
RDX: dffffc0000000000 RSI: ffffffff8acacce0 RDI: ffffffff8b1d35e0
RBP: ffffc9000bd471f0 R08: ffffffff911ef5af R09: 1ffffffff223deb5
R10: dffffc0000000000 R11: fffffbfff223deb6 R12: ffff888022978000
R13: 1ffff110171c79a1 R14: dffffc0000000000 R15: ffff8880b8e3cd08
 context_switch kernel/sched/core.c:5385 [inline]
 __schedule+0x15b6/0x4660 kernel/sched/core.c:6701
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6868
 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6892
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 copy_pte_range mm/memory.c:1107 [inline]
 copy_pmd_range mm/memory.c:1168 [inline]
 copy_pud_range mm/memory.c:1205 [inline]
 copy_p4d_range mm/memory.c:1229 [inline]
 copy_page_range+0x2be5/0x3700 mm/memory.c:1323
 dup_mmap kernel/fork.c:769 [inline]
 dup_mm kernel/fork.c:1700 [inline]
 copy_mm+0x1751/0x1e30 kernel/fork.c:1749
 copy_process+0x16c9/0x3da0 kernel/fork.c:2510
 kernel_clone+0x24b/0x8a0 kernel/fork.c:2919
 __do_sys_clone kernel/fork.c:3062 [inline]
 __se_sys_clone kernel/fork.c:3046 [inline]
 __x64_sys_clone+0x1b7/0x230 kernel/fork.c:3046
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f54ef99e159
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:00007f54f0896fd8 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f54efc25fa0 RCX: 00007f54ef99e159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000002c9a4080
RBP: 00007f54efa35024 R08: ffffffffff600000 R09: ffffffffff600000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007f54efc26038 R14: 00007f54efc25fa0 R15: 00007fff1cd21dd8
 </TASK>

Crashes (21):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/05 21:43 linux-6.6.y 8b73de7da85f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/29 06:42 linux-6.6.y c5596480c50e 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/18 07:36 linux-6.6.y da47cbc25466 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2026/07/08 12:17 linux-6.6.y da47cbc25466 88a4b44c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2026/07/06 02:06 linux-6.6.y da47cbc25466 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/26 03:32 linux-6.6.y d1cfde2d5d15 7ff32d8b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/24 15:42 linux-6.6.y d1cfde2d5d15 302586aa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2026/06/22 22:58 linux-6.6.y d1cfde2d5d15 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/21 10:38 linux-6.6.y d1cfde2d5d15 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/19 11:37 linux-6.6.y 924b4a879cbb 570c59ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2026/05/18 12:27 linux-6.6.y eac8889a3a1c 55156e84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/05/17 19:24 linux-6.6.y eac8889a3a1c de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2026/04/15 15:40 linux-6.6.y 8cee53b8eaeb c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/04/05 04:57 linux-6.6.y 08667c1437c0 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/03/28 07:08 linux-6.6.y c09fbcd31ae6 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2026/01/25 06:11 linux-6.6.y cbb31f77b879 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/01/25 00:50 linux-6.6.y cbb31f77b879 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2026/01/19 18:52 linux-6.6.y cbb31f77b879 a9fc5226 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2025/12/31 06:17 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_clone
2025/12/12 09:20 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
2025/12/09 09:12 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in sys_clone
* Struck through repros no longer work on HEAD.