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INFO: rcu detected stall in syscall_enter_from_user_mode

Status: upstream: reported C repro on 2023/12/13 03:22
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+12eef28cd33986d05b97@syzkaller.appspotmail.com
First crash: 681d, last: 7d02h
Fix commit to backport (bisect log) :
tree: upstream
commit 5f6bd380c7bdbe10f7b4e8ddcceed60ce0714c6d
Author: Peter Zijlstra <peterz@infradead.org>
Date: Mon May 27 12:06:55 2024 +0000

  sched/rt: Remove default bandwidth control

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: INFO: rcu detected stall in syscall_exit_to_user_mode (log)
Repro: C syz .config
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2024/10/27 linux-5.15.y (ToT) 74cdd62cb470 C [report] INFO: rcu detected stall in syscall_exit_to_user_mode
2023/12/13 upstream (ToT) 88035e5694a8 C [report] INFO: rcu detected stall in sys_rename
2024/10/27 upstream (ToT) 850925a8133c C Didn't crash
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 INFO: rcu detected stall in syscall_enter_from_user_mode (2) 1 1 445d 445d 0/3 auto-obsoleted due to no activity on 2024/11/13 07:03
linux-6.1 INFO: rcu detected stall in syscall_enter_from_user_mode 1 1 842d 842d 0/3 auto-obsoleted due to no activity on 2023/10/13 06:46
upstream INFO: rcu detected stall in syscall_enter_from_user_mode (2) kernel 1 11 1017d 1307d 0/29 auto-obsoleted due to no activity on 2023/04/22 11:15
linux-6.1 INFO: rcu detected stall in syscall_enter_from_user_mode (3) origin:lts-only 1 C inconclusive 5 7d22h 239d 0/3 upstream: reported C repro on 2025/02/27 13:22
upstream INFO: rcu detected stall in syscall_enter_from_user_mode (3) kernel 1 5 682d 847d 0/29 auto-obsoleted due to no activity on 2024/03/11 14:48
upstream INFO: rcu detected stall in syscall_enter_from_user_mode kernel 1 2 1364d 1378d 0/29 closed as invalid on 2022/02/08 10:10
android-5-15 BUG: soft lockup in syscall_enter_from_user_mode 1 1 526d 526d 0/2 auto-obsoleted due to no activity on 2024/08/14 14:14
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/08/11 10:41 11m retest repro linux-5.15.y report log
2025/08/11 10:41 12m retest repro linux-5.15.y report log
2025/08/11 10:41 15m retest repro linux-5.15.y report log
2025/08/07 03:23 22m retest repro linux-5.15.y report log
2025/08/07 03:23 1h41m retest repro linux-5.15.y report log
2025/06/02 08:10 11m retest repro linux-5.15.y report log
2025/06/02 08:10 11m retest repro linux-5.15.y report log
2025/06/02 08:10 13m retest repro linux-5.15.y report log
2025/02/05 21:18 11m retest repro linux-5.15.y report log
2025/01/05 08:36 17m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2025/04/08 12:35 8h33m fix candidate upstream OK (1) job log
2024/04/19 06:07 1h20m bisect fix linux-5.15.y OK (0) job log log
2024/03/16 14:55 1h22m bisect fix linux-5.15.y OK (0) job log log
2024/02/13 18:43 2h11m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10502 jiffies, g=8621, q=105)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294956609-4294946107), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g8621 f0x2 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:28032 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 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:
NMI backtrace for cpu 1
CPU: 1 PID: 4411 Comm: syz.2.25 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__syscall_enter_from_user_work kernel/entry/common.c:93 [inline]
RIP: 0010:syscall_enter_from_user_mode+0x2a/0x70 kernel/entry/common.c:114
Code: 41 56 53 48 89 f3 49 89 fe 48 8b 7c 24 10 e8 3d f6 ff ff eb 31 eb 35 e8 74 b0 d4 f7 e8 6f ae d4 f7 fb 65 48 8b 05 f6 35 59 76 <48> 8b 70 08 40 f6 c6 3f 74 0b 4c 89 f7 5b 41 5e e9 21 f2 bc f7 48
RSP: 0018:ffffc900037fff08 EFLAGS: 00000286
RAX: ffff88801da81dc0 RBX: 000000000000000f RCX: ffa8d0dbffa37400
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a4c0
RBP: ffffc900037fff48 R08: dffffc0000000000 R09: fffffbfff1ad32b6
R10: fffffbfff1ad32b6 R11: 1ffffffff1ad32b5 R12: 0000000000000000
R13: 0000000000000000 R14: ffffc900037fff58 R15: 0000000000000000
 do_syscall_64+0x24/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd30a23bf79
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ffd969b0d80 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007fd30a4f6fa0 RCX: 00007fd30a23bf79
RDX: 00007ffd969b0d80 RSI: 00007ffd969b0eb0 RDI: 0000000000000021
RBP: 00007fd30a322f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fd30a4f6fa0 R14: 00007fd30a4f6fa0 R15: 0000000000000004
 </TASK>

Crashes (107):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/05 11:39 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/08/24 16:57 linux-5.15.y c79648372d02 bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2024/06/07 11:31 linux-5.15.y c61bd26ae81a 121701b6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2023/12/13 03:21 linux-5.15.y 8a1d809b0545 ebcad15c .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/07/07 01:14 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/06/13 15:55 linux-5.15.y 1c700860e8bc 98683f8f .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/22 14:23 linux-5.15.y 0c935c049b5c c6512ef7 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/10/17 15:13 linux-5.15.y 29e53a5b1c4f 7adf5298 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/10/02 10:50 linux-5.15.y 43bb85222e53 267f56c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/09/21 20:37 linux-5.15.y 43bb85222e53 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in syscall_enter_from_user_mode
2025/09/18 20:54 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in syscall_enter_from_user_mode
2025/09/18 05:48 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-perf INFO: rcu detected stall in syscall_enter_from_user_mode
2025/09/16 23:52 linux-5.15.y 43bb85222e53 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/09/04 00:46 linux-5.15.y 01879f56bdde 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/09/02 08:32 linux-5.15.y 01879f56bdde 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/08/30 20:43 linux-5.15.y 01879f56bdde 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/08/18 01:55 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/08/15 13:28 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/08/13 23:38 linux-5.15.y c79648372d02 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/07/23 01:20 linux-5.15.y c79648372d02 8e9d1dc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/07/17 02:44 linux-5.15.y 89950c454265 44f8051e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/07/05 16:41 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/06/30 05:06 linux-5.15.y 3dea0e7f549e fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/06/18 09:25 linux-5.15.y 1c700860e8bc e77fae15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/06/07 13:14 linux-5.15.y 1c700860e8bc 4826c28e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/06/06 14:38 linux-5.15.y 1c700860e8bc 9fa58bba .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/06/05 07:59 linux-5.15.y 1c700860e8bc 6b6b5f21 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/05/18 20:37 linux-5.15.y a68c15152131 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/05/05 19:44 linux-5.15.y 16fdf2c7111b 6ca47dd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/05/05 09:19 linux-5.15.y 16fdf2c7111b b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/21 15:13 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/20 01:11 linux-5.15.y f7347f400572 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/16 06:57 linux-5.15.y f7347f400572 a95239b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/15 14:40 linux-5.15.y f7347f400572 23b969b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/14 01:38 linux-5.15.y f7347f400572 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/11 00:27 linux-5.15.y f7347f400572 1ef3ab4d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/10 07:17 linux-5.15.y 0c935c049b5c 988b336c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/09 19:40 linux-5.15.y 0c935c049b5c 47d015b1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/07 06:55 linux-5.15.y 0c935c049b5c 1c65791e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/05 06:50 linux-5.15.y 0c935c049b5c c53ea9c9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/01 10:36 linux-5.15.y 0c935c049b5c 36d76a97 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/04/01 06:06 linux-5.15.y 0c935c049b5c 36d76a97 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/31 03:32 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/30 01:53 linux-5.15.y 0c935c049b5c d3999433 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/20 12:37 linux-5.15.y 0c935c049b5c 9209bc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/16 02:32 linux-5.15.y 0c935c049b5c e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/14 08:52 linux-5.15.y 0c935c049b5c e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/03/12 04:52 linux-5.15.y c16c81c81336 ee70e6db .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/02/27 13:40 linux-5.15.y c16c81c81336 6a8fcbc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/02/12 16:41 linux-5.15.y c16c81c81336 b27c2402 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/01/19 18:47 linux-5.15.y 4735586da88e f2cb035c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2025/01/06 18:35 linux-5.15.y 91786f140358 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2024/12/06 04:44 linux-5.15.y 0a51d2d4527b 29f61fce .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
2024/11/13 18:11 linux-5.15.y 3c17fc483905 bb3f8425 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in syscall_enter_from_user_mode
* Struck through repros no longer work on HEAD.