INFO: rcu detected stall in sys_clone (2)

Status: upstream: reported C repro on 2024/03/27 00:16
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+a871499fe9cf68fa0d04@syzkaller.appspotmail.com
First crash: 885d, last: 11h30m
Fix commit to backport (bisect log) :
tree: upstream
commit e634134180885574d1fe7aa162777ba41e7fcd5b
Author: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Mon May 27 15:39:54 2024 +0000

  net/sched: taprio: make q->picos_per_byte available to fill_sched_entry()

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: INFO: rcu detected stall in newfstatat (log)
Repro: C syz .config
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2024/06/05 linux-5.15.y (ToT) c61bd26ae81a C [report] INFO: rcu detected stall in security_file_open
2024/04/20 upstream (ToT) 977b1ef51866 C [report] INFO: rcu detected stall in worker_thread
2024/06/05 upstream (ToT) 32f88d65f01b C 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 sys_clone 1 syz, C done 8 297d 382d 2/2 fixed on 2025/12/06 23:11
linux-5.15 INFO: rcu detected stall in sys_clone 1 1 996d 996d 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 1143d 1216d 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 2370d 2486d 0/29 auto-closed as invalid on 2020/06/01 05:26
upstream INFO: rcu detected stall in sys_clone (4) kernel 1 1 1886d 1886d 0/29 auto-closed as invalid on 2021/09/27 17:49
upstream INFO: rcu detected stall in sys_clone (3) mm 1 2 2222d 2244d 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 1557d 1557d 0/29 auto-closed as invalid on 2022/08/23 03:28
upstream INFO: rcu detected stall in sys_clone kernel 1 1 2543d 2543d 13/29 fixed on 2019/10/09 10:54
upstream INFO: rcu detected stall in sys_clone (8) mm 1 syz, C error 495 2d14h 883d 0/29 upstream: reported C repro on 2024/03/29 00:16
linux-4.19 INFO: rcu detected stall in sys_clone 1 2 2441d 2459d 0/1 auto-closed as invalid on 2020/04/21 05:46
upstream INFO: rcu detected stall in sys_clone (5) kernfs 1 5 1691d 1791d 0/29 closed as invalid on 2022/02/08 10:00
upstream INFO: rcu detected stall in sys_clone (7) fs 1 1 1292d 1292d 0/29 auto-obsoleted due to no activity on 2023/05/14 17:18
linux-6.1 INFO: rcu detected stall in sys_clone (2) origin:upstream missing-backport 1 syz, C error 106 21h59m 891d 0/3 upstream: reported C repro on 2024/03/20 15:17
linux-6.6 INFO: rcu detected stall in sys_clone (2) 1 20 31d 263d 0/2 upstream: reported on 2025/12/09 09:13
android-5-10 BUG: soft lockup in sys_clone 1 1 781d 781d 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 356d 356d 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 83d 83d 0/2 premoderation: reported on 2026/06/07 05:26
android-5-10 BUG: soft lockup in sys_clone (3) 1 1 208d 208d 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 718d 861d 0/2 auto-obsoleted due to no activity on 2024/12/19 12:14
upstream BUG: soft lockup in sys_clone kernel 1 3 2345d 2349d 0/29 closed as invalid on 2020/05/29 21:04
▶ ▼ Last patch testing requests (9)
Created Duration User Patch Repo Result
2025/09/29 23:26 12m retest repro linux-5.15.y report log
2025/09/29 23:26 11m retest repro linux-5.15.y report log
2025/09/29 23:26 14m retest repro linux-5.15.y report log
2025/06/19 06:54 13m retest repro linux-5.15.y report log
2025/06/19 06:54 14m retest repro linux-5.15.y report log
2025/04/04 12:14 10m retest repro linux-5.15.y report log
2025/04/04 12:14 13m retest repro linux-5.15.y report log
2024/12/22 07:16 11m retest repro linux-5.15.y report log
2024/10/12 20:15 17m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/09/12 19:45 5h35m fix candidate upstream OK (1) job log
2024/06/03 14:27 1h11m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...0: (1 GPs behind) idle=d2f/1/0x4000000000000000 softirq=4869/4873 fqs=2100 
	(detected by 0, t=10505 jiffies, g=3637, q=348)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 3518 Comm: syz-executor155 Not tainted 5.15.156-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
RIP: 0010:debug_deactivate+0x3/0x1e0 kernel/time/hrtimer.c:480
Code: 43 c9 10 00 0f 0b e9 0b ff ff ff e8 37 c9 10 00 e8 aa fa 90 ff e9 b7 fc ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 41 56 <53> 48 89 fb e8 14 c9 10 00 48 89 df 48 c7 c6 20 bc 8c 8a e8 45 de
RSP: 0018:ffffc90000dd0d48 EFLAGS: 00000046
RAX: ffffffff816f6369 RBX: ffff8880b9b2a2c8 RCX: ffff888022c80000
RDX: 0000000000010002 RSI: 0000000000000001 RDI: ffff88807915db40
RBP: ffffc90000dd0eb0 R08: ffffffff816f635c R09: ffff88807915db48
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880b9b2a200
R13: ffff8880b9b2a280 R14: ffff88807915db40 R15: dffffc0000000000
FS:  00005555570d4380(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555570d4ca8 CR3: 0000000019cb3000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __run_hrtimer kernel/time/hrtimer.c:1654 [inline]
 __hrtimer_run_queues+0x31d/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:unwind_next_frame+0x14f/0x1fa0
Code: 83 15 00 00 49 8d 6f 35 49 89 ec 49 c1 ec 03 41 0f b6 04 14 84 c0 0f 85 f1 16 00 00 4c 0f be 6d 00 48 8b 44 24 28 80 3c 10 00 <48> 8b 5c 24 08 74 12 48 89 df e8 c2 98 91 00 48 ba 00 00 00 00 00
RSP: 0018:ffffc90002c97488 EFLAGS: 00000246
RAX: 1ffff92000592ebd RBX: 0000000000000000 RCX: ffffffff8a272900
RDX: dffffc0000000000 RSI: ffffc90002c98000 RDI: ffffffff8138883b
RBP: ffffc90002c975d5 R08: dffffc0000000001 R09: ffffc90002c975a0
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000592eba
R13: 0000000000000000 R14: ffffffff8138a91f R15: ffffc90002c975a0
 __unwind_start+0x59d/0x720 arch/x86/kernel/unwind_orc.c:704
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 arch_stack_walk+0xdb/0x140 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc+0xba/0xf0 mm/kasan/common.c:513
 kasan_kmalloc include/linux/kasan.h:264 [inline]
 __kmalloc+0x168/0x300 mm/slub.c:4407
 kmalloc include/linux/slab.h:596 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 lsm_cred_alloc security/security.c:539 [inline]
 security_prepare_creds+0x48/0x130 security/security.c:1725
 prepare_creds+0x459/0x610 kernel/cred.c:291
 copy_creds+0x149/0xca0 kernel/cred.c:365
 copy_process+0x8a7/0x3ef0 kernel/fork.c:2070
 kernel_clone+0x210/0x960 kernel/fork.c:2604
 __do_sys_clone kernel/fork.c:2721 [inline]
 __se_sys_clone kernel/fork.c:2705 [inline]
 __x64_sys_clone+0x23f/0x290 kernel/fork.c:2705
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbc98444e63
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffedba542b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbc98444e63
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000010
R10: 00005555570d4650 R11: 0000000000000246 R12: 0000000000000001
R13: 000000000002efa9 R14: 00007ffedba543dc R15: 0000000000000003
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.888 msecs

Crashes (185):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/19 12:17 linux-5.15.y c52b9710c83d af24b050 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_clone
2025/02/26 02:09 linux-5.15.y c16c81c81336 d34966d1 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in sys_clone
2025/08/02 12:46 linux-5.15.y c79648372d02 7368264b .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: soft lockup in sys_clone
2026/08/29 01:02 linux-5.15.y 28c35638ec51 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/27 08:07 linux-5.15.y 945fa863f02c a2b77b9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/26 12:12 linux-5.15.y 945fa863f02c 6a91adb4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/25 09:12 linux-5.15.y 945fa863f02c 614e416a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/24 02:08 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/23 19:27 linux-5.15.y 945fa863f02c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/19 07:21 linux-5.15.y aabd761612db 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/18 21:42 linux-5.15.y aabd761612db 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/17 07:34 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/17 03:04 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/16 18:21 linux-5.15.y aabd761612db 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/14 19:05 linux-5.15.y aabd761612db 6f9b3e89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/09 20:24 linux-5.15.y aabd761612db 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/08 22:07 linux-5.15.y aabd761612db 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/06 10:13 linux-5.15.y 6e2fd6534337 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/08/03 03:41 linux-5.15.y 6e2fd6534337 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/31 08:50 linux-5.15.y 6e2fd6534337 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/27 07:14 linux-5.15.y 674f684f7c61 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/26 05:23 linux-5.15.y 674f684f7c61 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/26 00:30 linux-5.15.y 674f684f7c61 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/23 07:59 linux-5.15.y c86c4726e7f0 881ce5c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/21 08:25 linux-5.15.y c86c4726e7f0 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/20 04:24 linux-5.15.y c86c4726e7f0 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/18 02:52 linux-5.15.y c86c4726e7f0 8aaff637 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/17 02:53 linux-5.15.y c86c4726e7f0 71b49442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/16 21:54 linux-5.15.y c86c4726e7f0 71b49442 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/16 05:00 linux-5.15.y c86c4726e7f0 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/13 10:49 linux-5.15.y c86c4726e7f0 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/12 21:35 linux-5.15.y c86c4726e7f0 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/12 13:23 linux-5.15.y c86c4726e7f0 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/11 15:29 linux-5.15.y c86c4726e7f0 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/08 06:38 linux-5.15.y c86c4726e7f0 76cdc0c0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/04 08:56 linux-5.15.y eceeec79dbc6 fcece630 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/03 06:20 linux-5.15.y eceeec79dbc6 58bf2096 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/07/02 09:07 linux-5.15.y eceeec79dbc6 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/28 22:17 linux-5.15.y eceeec79dbc6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/28 18:03 linux-5.15.y eceeec79dbc6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/28 13:26 linux-5.15.y eceeec79dbc6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/26 19:13 linux-5.15.y eceeec79dbc6 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/23 21:17 linux-5.15.y eceeec79dbc6 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/23 18:22 linux-5.15.y eceeec79dbc6 4b1d8f01 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/23 01:17 linux-5.15.y eceeec79dbc6 5a630be6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/22 11:52 linux-5.15.y eceeec79dbc6 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/13 02:11 linux-5.15.y dc027a595035 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/08 13:38 linux-5.15.y dc027a595035 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/06/07 19:08 linux-5.15.y dc027a595035 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in sys_clone
2026/05/24 18:18 linux-5.15.y 241d66fa280c c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_clone
2024/03/27 00:15 linux-5.15.y 9465fef4ae35 454571b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_clone
2024/08/14 21:44 linux-5.15.y 7e89efd3ae1c e6b88e20 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in sys_clone
2026/03/21 22:37 linux-5.15.y 91d48252ad4b 5b92003d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf BUG: soft lockup in sys_clone
* Struck through repros no longer work on HEAD.