INFO: rcu detected stall in sys_futex

Status: auto-obsoleted due to no activity on 2024/04/10 17:08
Reported-by: syzbot+a4b1213abbe3ecd9ed41@syzkaller.appspotmail.com
First crash: 1126d, last: 952d
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 INFO: rcu detected stall in futex (2) origin:lts-only 1 syz, C inconclusive 71 3d23h 284d 0/2 upstream: reported C repro on 2025/10/31 01:02
upstream INFO: rcu detected stall in sys_futex (7) prio:high kernel 1 syz error error 139 6d19h 777d 0/29 upstream: reported syz repro on 2024/06/24 16:48
upstream INFO: rcu detected stall in sys_futex (3) mm 1 959 2406d 2455d 0/29 auto-closed as invalid on 2020/03/08 12:44
upstream INFO: rcu detected stall in sys_futex (2) kernel 1 6 2574d 2718d 0/29 auto-closed as invalid on 2019/10/25 14:11
upstream INFO: rcu detected stall in sys_futex (4) kernel 1 1 1655d 1655d 0/29 closed as invalid on 2022/02/08 10:00
linux-5.15 INFO: rcu detected stall in sys_futex (2) origin:lts-only 1 syz, C error 96 2h24m 796d 0/3 upstream: reported C repro on 2024/06/05 16:49
upstream INFO: rcu detected stall in sys_futex kernel 1 1 2780d 2780d 0/29 closed as invalid on 2018/12/31 04:10
linux-6.6 INFO: rcu detected stall in futex origin:lts-only 1 syz, C done 6 348d 365d 2/2 fixed on 2025/10/06 10:09
linux-6.1 INFO: rcu detected stall in sys_futex origin:lts-only 1 syz, C done 68 3d01h 1132d 0/3 upstream: reported C repro on 2023/07/05 11:35
upstream INFO: rcu detected stall in sys_futex (5) kernel 1 12 1386d 1631d 0/29 auto-obsoleted due to no activity on 2023/02/12 18:33
upstream INFO: rcu detected stall in sys_futex (6) kernel 1 10 955d 1190d 0/29 auto-obsoleted due to no activity on 2024/03/29 00:57

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=d45/1/0x4000000000000000 softirq=73993/73994 fqs=0 
	(detected by 1, t=10506 jiffies, g=87881, q=65)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 25610 Comm: syz-executor.0 Not tainted 5.15.145-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
RIP: 0010:lock_acquire+0x239/0x4f0 kernel/locking/lockdep.c:5626
Code: 4c 89 f7 e8 79 5d 67 00 48 c7 44 24 60 00 00 00 00 9c 8f 44 24 60 42 80 3c 2b 00 74 08 4c 89 f7 e8 dc 5c 67 00 f6 44 24 61 02 <0f> 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e
RSP: 0018:ffffc90000007b40 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 1ffff92000000f74 RCX: ffffffff81633742
RDX: dffffc0000000000 RSI: ffffffff8a8b2220 RDI: ffffffff8ad88080
RBP: ffffc90000007c98 R08: dffffc0000000000 R09: fffffbfff1f79e57
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000000f70
R13: dffffc0000000000 R14: ffffc90000007ba0 R15: 0000000000000046
FS:  00005555570c0480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f8406dfc988 CR3: 00000000740b2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:363 [inline]
 advance_sched+0x47/0x940 net/sched/sch_taprio.c:716
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd4/0x130 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 a2 63 a4 f7 f6 44 24 21 02 75 4e 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> e7 ba 31 f7 65 8b 05 58 f6 dc 75 85 c0 74 3f 48 c7 04 24 0e 36
RSP: 0018:ffffc900010ff880 EFLAGS: 00000206
RAX: 235bc0b102528800 RBX: 1ffff9200021ff14 RCX: ffffffff913c6f03
RDX: dffffc0000000000 RSI: ffffffff8a8b0f80 RDI: 0000000000000001
RBP: ffffc900010ff910 R08: ffffffff8186a260 R09: ffffed1017345441
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 1ffff9200021ff10 R14: ffffc900010ff8a0 R15: 0000000000000246
 unlock_hrtimer_base kernel/time/hrtimer.c:1017 [inline]
 hrtimer_try_to_cancel+0x3b2/0x410 kernel/time/hrtimer.c:1336
 hrtimer_cancel+0x12/0x50 kernel/time/hrtimer.c:1443
 futex_wait+0x615/0x740 kernel/futex/core.c:2996
 do_futex+0x1414/0x1810 kernel/futex/core.c:3982
 __do_sys_futex kernel/futex/core.c:4059 [inline]
 __se_sys_futex+0x407/0x490 kernel/futex/core.c:4040
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f8406cdbce9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff3ec246e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00000000000d9f6a RCX: 00007f8406cdbce9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8406dfaf8c
RBP: 0000000000000032 R08: 00007f8406dfaf8c R09: 00007f8406dfaf8c
R10: 00007fff3ec24820 R11: 0000000000000246 R12: 00007f8406dfaf8c
R13: 00000000000d9f9c R14: 00007fff3ec24840 R15: 00007fff3ec24820
 </TASK>
rcu: rcu_preempt kthread starved for 10506 jiffies! g87881 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:25984 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 25613 Comm: syz-executor.4 Not tainted 5.15.145-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
 update_process_times+0x196/0x200 kernel/time/timer.c:1788
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
 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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xa93/0xd90 kernel/smp.c:969
Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 cc cb 0b 00 41 83 e7 01 75 07 e8 61 c8 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00
RSP: 0018:ffffc900026d7ac0 EFLAGS: 00000246
RAX: ffffffff81745f34 RBX: 1ffff110173483c1 RCX: 0000000000040000
RDX: ffffc9000c9e3000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900026d7bf0 R08: ffffffff81745f04 R09: ffffed10173674f3
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff8880b9a41e08 R14: ffff8880b9b3a780 R15: 0000000000000001
 clock_was_set+0x7b6/0x880 kernel/time/hrtimer.c:974
 do_settimeofday64+0x673/0x7e0 kernel/time/timekeeping.c:1328
 __do_sys_clock_settime kernel/time/posix-timers.c:1119 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1107 [inline]
 __x64_sys_clock_settime+0x232/0x270 kernel/time/posix-timers.c:1107
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f328025ace9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f327e7dc0c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007f3280379f80 RCX: 00007f328025ace9
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00007f32802a747a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f3280379f80 R15: 00007fffb32b89f8
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/01/01 17:07 linux-5.15.y d93fa2c78854 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_futex
2023/11/01 09:04 linux-5.15.y 12952a23a5da 69904c9f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_futex
2023/09/02 13:29 linux-5.15.y 8f790700c974 696ea0d2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_futex
2023/07/11 05:38 linux-5.15.y d54cfc420586 52ae002a .config console log report info ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in sys_futex
* Struck through repros no longer work on HEAD.