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INFO: rcu detected stall in sys_getpid

Status: auto-obsoleted due to no activity on 2026/03/20 23:07
Subsystems: kernel
[Documentation on labels]
First crash: 250d, last: 100d
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in sys_getpid origin:lts-only 1 C inconclusive 4 126d 205d 0/2 upstream: reported C repro on 2025/09/06 16:11
linux-5.15 INFO: rcu detected stall in sys_getpid 1 1 642d 642d 0/3 auto-obsoleted due to no activity on 2024/10/04 19:18
linux-6.1 INFO: rcu detected stall in sys_getpid 1 1 340d 340d 0/3 auto-obsoleted due to no activity on 2025/08/03 12:49
linux-6.1 INFO: rcu detected stall in sys_getpid (2) 1 2 58d 118d 0/3 upstream: reported on 2025/12/02 23:35
linux-5.15 INFO: rcu detected stall in sys_getpid (2) origin:lts-only 1 C error 21 27d 485d 0/3 upstream: reported C repro on 2024/11/30 21:19

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6807/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=14885, q=1038 ncpus=2)
task:syz.5.291       state:R  running task     stack:25552 pid:6807  tgid:6806  ppid:5835   task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319
Code: 48 8d 3d 33 a3 29 04 48 c7 c6 11 fb 77 8d 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 31 c0 83 3d 17 59 26 04 00 74 1e 83 3d 2a 88 26 04 00
RSP: 0018:ffffc9000b85fe90 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888077786d80 RCX: 0000000000080000
RDX: ffffc9000d21c000 RSI: 0000000000007b02 RDI: 0000000000007b03
RBP: 0000000000000087 R08: ffffffff818cf788 R09: ffffffff8df41a20
R10: dffffc0000000000 R11: fffffbfff1f0440f R12: ffff888077786e98
R13: dffffc0000000000 R14: ffff888077786e90 R15: 0000000000000010
 rcu_read_unlock include/linux/rcupdate.h:895 [inline]
 __task_pid_nr_ns+0x31e/0x490 kernel/pid.c:520
 task_tgid_vnr include/linux/pid.h:298 [inline]
 __ia32_sys_getpid+0x1e/0x30 kernel/sys.c:1001
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd7609865e7
RSP: 002b:00007fd76182ba48 EFLAGS: 00000206 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007fd76182bbb0 RCX: 00007fd7609865e7
RDX: 00007fd76182ba80 RSI: 00007fd76182bbb0 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007fd760be6038 R14: 00007fd760be5fa0 R15: 00007ffe921eb8a8
 </TASK>
rcu: rcu_preempt kthread starved for 10529 jiffies! g14885 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:27784 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 5e 83 b4 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 90 0c 00 f3 0f 1e fa fb f4 <e9> 33 83 b4 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 000002c6
RAX: ac474848f429e900 RBX: ffffffff81978fda RCX: ac474848f429e900
RDX: 0000000000000001 RSI: ffffffff8d79261c RDI: ffffffff8bc08360
RBP: ffffffff8dc07ea8 R08: ffff8880b86336db R09: 1ffff110170c66db
R10: dffffc0000000000 R11: ffffed10170c66dc R12: ffffffff8f822070
R13: 1ffffffff1b92a68 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005591aa4174d8 CR3: 000000005a5c0000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x1ea/0x520 kernel/sched/idle.c:332
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430
 rest_init+0x2de/0x300 init/main.c:757
 start_kernel+0x3a7/0x400 init/main.c:1206
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/20 23:00 upstream d8ba32c5a460 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_getpid
2025/12/03 00:33 upstream 4a26e7032d7d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_getpid
2025/09/24 16:03 upstream cec1e6e5d1ab 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root INFO: rcu detected stall in sys_getpid
2025/08/10 08:25 upstream 038d61fd6422 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_getpid
2025/07/24 03:48 upstream 01a412d06bc5 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_getpid
* Struck through repros no longer work on HEAD.