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INFO: rcu detected stall in sys_exit_group

Status: upstream: reported on 2025/07/21 16:02
Reported-by: syzbot+48904dad9520cbb5ce21@syzkaller.appspotmail.com
First crash: 47d, last: 3d09h
▶ ▼ Similar bugs (15)
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 C unreliable inconclusive 90 425d 1422d 0/29 upstream: reported C repro on 2021/10/15 18:41
upstream INFO: rcu detected stall in sys_exit_group (6) mm 1 C 4 1802d 1808d 19/29 fixed on 2021/03/10 01:48
linux-5.15 INFO: rcu detected stall in sys_exit_group (2) 1 3 506d 541d 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 (3) origin:upstream 1 C error 17 28d 592d 0/3 upstream: reported C repro on 2024/01/23 11:05
linux-6.1 INFO: rcu detected stall in sys_exit_group (2) 1 1 739d 739d 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 850d 850d 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 801d 801d 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 2103d 2105d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in sys_exit_group (3) mm 1 8 2068d 2069d 0/29 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in sys_exit_group (4) mm 1 13 2068d 2068d 0/29 closed as invalid on 2020/01/09 08:13
upstream INFO: rcu detected stall in sys_exit_group (5) mm 1 1 1989d 1989d 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 296d 329d 0/3 auto-obsoleted due to no activity on 2025/02/22 19:05
upstream INFO: rcu detected stall in sys_exit_group kernel 1 C done 1 2184d 2180d 13/29 fixed on 2019/10/09 10:54
android-5-10 BUG: soft lockup in sys_exit_group 1 1 412d 412d 0/2 auto-obsoleted due to no activity on 2024/10/19 10:22
android-5-15 BUG: soft lockup in sys_exit_group 1 C error 7 374d 517d 0/2 auto-obsoleted due to no activity on 2024/12/07 01:30

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5157/2:b..l P5787/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=47633, q=534 ncpus=2)
task:udevd           state:R  running task     stack:23144 pid:5787  ppid:5157   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215
Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d bc 01 c5 0c 48 89 de 5b e9 a3 75 56 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 50 2a 7e 7e 65 8b 15 51 2a 7e 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900044ff4f8 EFLAGS: 00000202
RAX: ffffffff813aa191 RBX: ffffc900044ff570 RCX: 0000000000000000
RDX: ffff888079968000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff888079968000 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff8150f24e
R13: 1ffff9200089fed0 R14: dffffc0000000000 R15: 1ffff9200089feae
 unwind_get_return_address+0x71/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf7/0x1f0 mm/page_owner.c:128
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2475
 release_pages+0x1fa0/0x2220 mm/swap.c:1022
 tlb_batch_pages_flush mm/mmu_gather.c:98 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:293 [inline]
 tlb_flush_mmu+0x368/0x4f0 mm/mmu_gather.c:300
 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:392
 exit_mmap+0x3f0/0xb50 mm/mmap.c:3315
 __mmput+0x118/0x3c0 kernel/fork.c:1355
 exit_mm+0x1da/0x2c0 kernel/exit.c:569
 do_exit+0x88e/0x23c0 kernel/exit.c:870
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 __do_sys_exit_group kernel/exit.c:1035 [inline]
 __se_sys_exit_group kernel/exit.c:1033 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1033
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f138faf16c5
RSP: 002b:00007fff4bbfa2d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000056452d853f80 RCX: 00007f138faf16c5
RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000
RBP: 000056452d82f910 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fff4bbfa320 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
task:udevd           state:R  running task     stack:23144 pid:5157  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0xfa/0x110 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 unlock_task_sighand include/linux/sched/signal.h:750 [inline]
 do_send_sig_info kernel/signal.c:1313 [inline]
 group_send_sig_info+0x230/0x260 kernel/signal.c:1462
 kill_pid_info+0xf7/0x1f0 kernel/signal.c:1496
 kill_proc_info+0xd4/0x180 kernel/signal.c:1513
 kill_something_info kernel/signal.c:1610 [inline]
 __do_sys_kill kernel/signal.c:3823 [inline]
 __se_sys_kill+0x198/0x550 kernel/signal.c:3817
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f138fa5f357
RSP: 002b:00007fff4bbfa468 EFLAGS: 00000297 ORIG_RAX: 000000000000003e
RAX: ffffffffffffffda RBX: 00007fff4bbfa470 RCX: 00007f138fa5f357
RDX: 000056452d8301c0 RSI: 000000000000000f RDI: 00000000000016ab
RBP: 0000000000000000 R08: 0000000000000010 R09: 000056452d8378e0
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000
R13: 0000564523e90100 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10572 jiffies! g47633 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:26888 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148
Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d a3 36 3a 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6
RAX: aa6f94d36c904400 RBX: ffffffff8161923b RCX: aa6f94d36c904400
RDX: 0000000000000001 RSI: ffffffff8aaaba20 RDI: ffffffff8afc7040
RBP: ffffc90000187f20 R08: ffff8880b8f36d4b R09: 1ffff110171e6da9
R10: dffffc0000000000 R11: ffffed10171e6daa R12: ffffffff8e4a8f28
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110037cb780
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb7849c6098 CR3: 000000007dd48000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:170 [inline]
 do_idle+0x1eb/0x510 kernel/sched/idle.c:282
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/03 17:05 linux-6.6.y cc1a1c5b404a 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_exit_group
2025/07/22 10:50 linux-6.6.y d96eb99e2f0e 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_exit_group
2025/07/21 16:01 linux-6.6.y d96eb99e2f0e 56d87229 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_exit_group
* Struck through repros no longer work on HEAD.