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INFO: rcu detected stall in clone3 (2)

Status: upstream: reported on 2026/03/01 00:21
Reported-by: syzbot+ea4ad5aa0d82fee4b59b@syzkaller.appspotmail.com
First crash: 31d, last: 31d
▶ ▼ Similar bugs (17)
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 C inconclusive 2 117d 181d 0/2 upstream: reported C repro on 2025/10/02 07:48
upstream INFO: rcu detected stall in clone3 (5) mm 1 7 457d 667d 0/29 auto-obsoleted due to no activity on 2025/03/30 08:38
upstream INFO: rcu detected stall in clone3 mm 1 2 1540d 1566d 0/29 closed as invalid on 2022/02/08 10:10
linux-5.15 INFO: rcu detected stall in clone3 1 2 238d 273d 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 1388d 1388d 0/29 auto-closed as invalid on 2022/09/10 23:49
upstream INFO: rcu detected stall in clone3 (3) kernel 1 1 1137d 1137d 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 951d 1030d 0/29 auto-obsoleted due to no activity on 2023/11/22 09:08
upstream INFO: rcu detected stall in sys_clone3 (3) mm 1 26 381d 576d 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 495d 554d 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 1410d 1410d 0/29 auto-closed as invalid on 2022/08/20 13:01
linux-5.15 INFO: rcu detected stall in sys_clone3 1 1 544d 544d 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 674d 778d 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 816d 813d 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 356d 356d 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 411d 411d 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 676d 676d 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 84d 84d 0/2 premoderation: reported on 2026/01/07 17:53

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4319/1:b..l
	(detected by 1, t=10502 jiffies, g=7141, q=642)
task:syz.1.12        state:R  running task     stack:26352 pid: 4319 ppid:  4184 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc9000318f970 EFLAGS: 00000206
RAX: 4501dc9a69365500 RBX: ffff88807ea71dc0 RCX: 4501dc9a69365500
RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f800
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff203a618
R10: dffffc0000000000 R11: fffffbfff203a619 R12: 0000000000000000
R13: 0000000000000246 R14: ffffffff8c31eaa0 R15: ffff88807ea728b0
 copy_namespaces+0x10e/0x3e0 kernel/nsproxy.c:154
 copy_process+0x1834/0x3e20 kernel/fork.c:2293
 kernel_clone+0x23f/0x990 kernel/fork.c:2679
 __do_sys_clone3 kernel/fork.c:2954 [inline]
 __se_sys_clone3+0x312/0x3d0 kernel/fork.c:2938
 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: 0033:0x7f96dd0c3589
RSP: 002b:00007fff7a0f4a98 EFLAGS: 00000202 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f96dd07eb20 RCX: 00007f96dd0c3589
RDX: 00007f96dd07eb20 RSI: 0000000000000058 RDI: 00007fff7a0f4af0
RBP: 00007f96daeb76c0 R08: 00007f96daeb76c0 R09: 00007fff7a0f4bd7
R10: 0000000000000008 R11: 0000000000000202 R12: ffffffffffffffe8
R13: 000000000000006e R14: 00007fff7a0f4af0 R15: 00007fff7a0f4bd8
 </TASK>
rcu: rcu_preempt kthread starved for 8835 jiffies! g7141 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27760 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/01 00:20 linux-5.15.y 3330a8d33e08 43249bac .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.