INFO: rcu detected stall in sys_exit_group (3)

Status: upstream: reported C repro on 2024/01/23 11:05
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+6f38629d8f83a72bd6f7@syzkaller.appspotmail.com
First crash: 940d, last: 2d01h
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2024/02/23 upstream (ToT) ffd2cb6b718e C [report] INFO: rcu detected stall in syscall_exit_to_user_mode
▶ ▼ Similar bugs (17)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_exit_group (7) net 1 syz, C unreliable inconclusive 90 773d 1770d 0/29 upstream: reported C repro on 2021/10/15 18:41
upstream INFO: rcu detected stall in sys_exit_group (6) mm 1 syz, C 4 2150d 2156d 19/29 fixed on 2021/03/10 01:48
linux-5.15 INFO: rcu detected stall in sys_exit_group (2) 1 3 855d 889d 0/3 auto-obsoleted due to no activity on 2024/07/27 04:53
linux-6.1 INFO: rcu detected stall in sys_exit_group (2) 1 1 1087d 1087d 0/3 auto-obsoleted due to no activity on 2023/12/07 20:57
linux-6.1 INFO: rcu detected stall in sys_exit_group 1 1 1198d 1198d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:06
linux-5.15 INFO: rcu detected stall in sys_exit_group 1 1 1149d 1149d 0/3 auto-obsoleted due to no activity on 2023/10/06 21:30
upstream INFO: rcu detected stall in sys_exit_group (2) mm cgroups 1 56 2451d 2453d 0/29 closed as invalid on 2019/12/04 14:14
linux-6.6 INFO: rcu detected stall in sys_exit_group origin:upstream 1 syz, C error 16 48d 395d 0/2 upstream: reported C repro on 2025/07/21 16:02
upstream INFO: rcu detected stall in sys_exit_group (3) mm 1 8 2417d 2417d 0/29 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in sys_exit_group (4) mm 1 13 2416d 2417d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in sys_exit_group (5) mm 1 1 2337d 2337d 0/29 auto-closed as invalid on 2020/06/25 07:58
linux-5.15 INFO: rcu detected stall in sys_exit_group (3) 1 2 644d 677d 0/3 auto-obsoleted due to no activity on 2025/02/22 19:05
linux-5.15 INFO: rcu detected stall in sys_exit_group (4) origin:upstream 1 syz, C error 9 11d 336d 0/3 upstream: reported C repro on 2025/09/19 02:54
upstream INFO: rcu detected stall in sys_exit_group kernel 1 syz, C done 1 2532d 2528d 13/29 fixed on 2019/10/09 10:54
android-5-10 BUG: soft lockup in sys_exit_group 1 1 760d 760d 0/2 auto-obsoleted due to no activity on 2024/10/19 10:22
android-5-10 BUG: soft lockup in sys_exit_group (2) 1 1 203d 203d 0/2 auto-obsoleted due to no activity on 2026/04/29 20:43
android-5-15 BUG: soft lockup in sys_exit_group 1 syz, C error 7 722d 865d 0/2 auto-obsoleted due to no activity on 2024/12/07 01:30
▶ ▼ Fix bisection attempts (9)
Created Duration User Patch Repo Result
2025/05/28 19:35 12m bisect fix linux-6.1.y error job log
2025/04/24 14:19 1h55m bisect fix linux-6.1.y OK (0) job log log
2025/02/22 23:34 2h44m bisect fix linux-6.1.y OK (0) job log log
2024/12/29 04:40 2h00m bisect fix linux-6.1.y OK (0) job log log
2024/10/21 08:40 3h04m bisect fix linux-6.1.y OK (0) job log log
2024/09/20 04:31 1h45m bisect fix linux-6.1.y OK (0) job log log
2024/08/03 22:07 1h19m bisect fix linux-6.1.y OK (0) job log log
2024/06/08 12:48 1h13m bisect fix linux-6.1.y OK (0) job log log
2024/05/09 04:03 1h32m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (2 GPs behind) idle=41ac/1/0x4000000000000000 softirq=9784/9787 fqs=0
	(detected by 0, t=10504 jiffies, g=8785, q=8842 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4653 Comm: syz.0.244 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:60 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x4e/0x290 mm/kasan/generic.c:189
Code: e8 2f 41 81 f8 ff ff 01 00 0f 82 fa 01 00 00 49 bc 01 00 00 00 00 fc ff df 49 89 fe 49 c1 ee 03 49 ba 00 00 00 00 00 fc ff df <4f> 8d 1c 16 4c 8d 44 3e ff 4d 89 c1 49 c1 e9 03 4b 8d 1c 21 49 89
RSP: 0018:ffffc900001e0ad0 EFLAGS: 00000802
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81647b70
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e210ae8
RBP: ffffc900001e0c10 R08: 000000000001ffff R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c174 R12: dffffc0000000001
R13: dffffc0000000000 R14: 1ffffffff1c4215d R15: 1ffff9200003c16c
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000300 CR3: 000000000c88e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 cpumask_test_cpu include/linux/cpumask.h:444 [inline]
 cpu_online include/linux/cpumask.h:1030 [inline]
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0xc0/0x920 kernel/locking/lockdep.c:5687
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x6d/0x120 kernel/locking/spinlock.c:194
 debug_object_activate+0x2f2/0x4f0 lib/debugobjects.c:765
 debug_hrtimer_activate kernel/time/hrtimer.c:448 [inline]
 debug_activate kernel/time/hrtimer.c:502 [inline]
 enqueue_hrtimer+0x37/0x410 kernel/time/hrtimer.c:1097
 __run_hrtimer kernel/time/hrtimer.c:1768 [inline]
 __hrtimer_run_queues+0x63e/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:stackdepot_memcmp lib/stackdepot.c:289 [inline]
RIP: 0010:find_stack lib/stackdepot.c:306 [inline]
RIP: 0010:__stack_depot_save+0x180/0x480 lib/stackdepot.c:452
Code: 85 ed 74 63 89 ca eb 09 4d 8b 6d 00 4d 85 ed 74 56 41 39 6d 08 75 f1 41 39 4d 0c 75 eb 31 f6 49 8b 3c f6 49 3b 7c f5 18 75 de <48> ff c6 39 f2 75 ee 4d 85 ed 74 09 b8 ff ff ff 07 41 23 45 10 65
RSP: 0018:ffffc90003417638 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000000f
RDX: 000000000000000f RSI: 0000000000000007 RDI: ffffffff81c32f88
RBP: 00000000098c85d6 R08: 0000000000000800 R09: ffff88823b400000
R10: 00000000a2650914 R11: 000000000c9e58e6 R12: 0000000000000001
R13: ffff8880307f42b0 R14: ffffc900034176a0 R15: 00000000000c85d6
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_set_track+0x60/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x27/0x40 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1f0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x133/0x1b0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free_bulk+0x364/0x480 mm/slub.c:3805
 mt_free_bulk lib/maple_tree.c:164 [inline]
 mt_destroy_walk+0xdd/0x6b0 lib/maple_tree.c:5639
 mte_destroy_walk lib/maple_tree.c:5688 [inline]
 __mt_destroy+0x142/0x250 lib/maple_tree.c:6494
 exit_mmap+0x5d8/0x970 mm/mmap.c:3280
 __mmput+0x118/0x3a0 kernel/fork.c:1206
 exit_mm+0x24d/0x350 kernel/exit.c:572
 do_exit+0x958/0x2570 kernel/exit.c:874
 do_group_exit+0x229/0x2e0 kernel/exit.c:1030
 __do_sys_exit_group kernel/exit.c:1041 [inline]
 __se_sys_exit_group kernel/exit.c:1039 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1039
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdb92b9e0d9
Code: Unable to access opcode bytes at 0x7fdb92b9e0af.
RSP: 002b:00007ffea58299e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdb92b9e0d9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffea5829a4c R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000e3
R13: 00000000000927c0 R14: 000000000001830c R15: 00007ffea5829aa0
 </TASK>
rcu: rcu_preempt kthread starved for 10504 jiffies! g8785 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:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 4362 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0x1163/0x1250 kernel/smp.c:998
Code: df 75 0a e8 ff fb 0a 00 e9 34 ff ff ff f3 90 41 0f b6 04 1c 84 c0 75 14 41 f7 07 01 00 00 00 0f 84 17 ff ff ff e8 dd fb 0a 00 <eb> e1 44 89 f9 80 e1 07 80 c1 03 38 c1 7c df 4c 89 ff e8 76 28 5c
RSP: 0018:ffffc90003337800 EFLAGS: 00000293
RAX: ffffffff81773243 RBX: dffffc0000000000 RCX: ffff88801a7d3c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003337960 R08: ffffffff90b10247 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: 1ffff110171e8219
R13: ffff8880b8e3bdc0 R14: 0000000000000001 R15: ffff8880b8f410c8
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb9395da08 CR3: 000000000c88e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1165
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1574 [inline]
 text_poke_bp_batch+0x2b7/0x850 arch/x86/kernel/alternative.c:1774
 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207
 static_key_enable+0x16/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xba/0x470 mm/kfence/core.c:821
 process_one_work+0x8ab/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaf5/0x12a0 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (35):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/19 06:08 linux-6.1.y e4f7d8be268e 1e72964b .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/04/04 06:30 linux-6.1.y 347385861c50 51c4dcff .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/03/28 05:00 linux-6.1.y e5cd595e23c1 120789fd .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/02/25 03:23 linux-6.1.y 81e1dc2f7001 8d446f15 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/02/23 04:57 linux-6.1.y 8b4118fabd6e 8d446f15 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/07/17 15:19 linux-6.1.y 090666d3cc90 7f27c57a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/07/09 07:33 linux-6.1.y 090666d3cc90 b9f1ceaa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/06/14 03:44 linux-6.1.y 228da13e907e 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_exit_group
2026/06/13 10:58 linux-6.1.y 228da13e907e 1d2f3589 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/05/20 01:48 linux-6.1.y c27210688955 0909d65f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/04/21 00:12 linux-6.1.y 7c87defbd336 e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/04/14 21:28 linux-6.1.y 8e8fc038cad5 362d1323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/04/12 08:50 linux-6.1.y 8e8fc038cad5 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/04/08 03:50 linux-6.1.y 1989cd3d56e2 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/03/25 05:17 linux-6.1.y f2ddafa93a25 74e70d19 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/02/18 02:13 linux-6.1.y 8ce36b2849ef 06ec4f7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/02/06 05:43 linux-6.1.y cd9b81672742 f03c4191 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/01/29 07:54 linux-6.1.y cd9b81672742 0adc945e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2026/01/22 21:40 linux-6.1.y cd9b81672742 82c9c083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_exit_group
2025/12/13 21:32 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/10/12 05:45 linux-6.1.y 882efbdd9d34 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in sys_exit_group
2025/09/25 11:16 linux-6.1.y 7b34dc04e4ff 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/08/09 16:35 linux-6.1.y 3594f306da12 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/07/14 12:24 linux-6.1.y dfc486ec9cce d8fc7335 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/06/25 08:36 linux-6.1.y 58485ff1a74f 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/05/31 13:31 linux-6.1.y da3c5173c55f 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/05/28 21:22 linux-6.1.y da3c5173c55f 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/03/21 01:49 linux-6.1.y 344a09659766 62330552 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2025/01/23 20:16 linux-6.1.y 75cefdf153f5 521b0ce3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/11/12 22:08 linux-6.1.y d7039b844a1c 62026c85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/08/17 18:12 linux-6.1.y 117ac406ba90 dbc93b08 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/06/24 05:10 linux-6.1.y eb44d83053d6 edc5149a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/03/14 22:54 linux-6.1.y 61adba85cc40 d615901c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/01/25 22:20 linux-6.1.y 8fd7f4462453 cc4a4020 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
2024/01/23 11:04 linux-6.1.y 8fd7f4462453 1c0ecc51 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_exit_group
* Struck through repros no longer work on HEAD.