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INFO: rcu detected stall in cleanup_mnt (2)

Status: upstream: reported syz repro on 2024/08/10 23:43
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+09e7336b5c7f5b7fa856@syzkaller.appspotmail.com
First crash: 48d, last: 5d04h
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2024/09/01 linux-5.15.y (ToT) fa93fa65db6e C [report] INFO: rcu detected stall in tcp_setsockopt
2024/09/01 upstream (ToT) 6cd90e5ea72f C Didn't crash
▶ ▼ Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in cleanup_mnt 1 475d 475d 0/3 auto-obsoleted due to no activity on 2023/09/19 04:00
upstream INFO: rcu detected stall in cleanup_mnt (2) block 1 1011d 1011d 0/28 closed as invalid on 2022/02/08 10:10
linux-6.1 INFO: rcu detected stall in cleanup_mnt (2) 1 104d 104d 0/3 auto-obsoleted due to no activity on 2024/09/23 19:34
linux-6.1 INFO: rcu detected stall in cleanup_mnt 1 420d 420d 0/3 auto-obsoleted due to no activity on 2023/11/13 00:06
upstream INFO: rcu detected stall in cleanup_mnt exfat 1 1543d 1543d 0/28 auto-closed as invalid on 2020/09/06 14:28
upstream INFO: rcu detected stall in cleanup_mnt (3) reiserfs block 2 486d 496d 0/28 auto-obsoleted due to no activity on 2023/08/29 03:36

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=b31/1/0x4000000000000000 softirq=6200/6202 fqs=2 
	(detected by 1, t=10505 jiffies, g=6713, q=385)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3665 Comm: syz-executor Not tainted 5.15.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:__lock_release kernel/locking/lockdep.c:5279 [inline]
RIP: 0010:lock_release+0x704/0x9a0 kernel/locking/lockdep.c:5643
Code: e9 fa f9 ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 2e fa ff ff 48 89 df e8 59 50 67 00 e9 21 fa ff ff 48 8d 8c 24 80 00 00 00 <80> e1 07 80 c1 03 38 c1 0f 8c 94 fa ff ff 48 8d bc 24 80 00 00 00
RSP: 0000:ffffc90000007b80 EFLAGS: 00000002
RAX: 0000000000000004 RBX: 0000000000000046 RCX: ffffc90000007c00
RDX: 1ffff92000000f80 RSI: ffffffff8a8b3820 RDI: ffffffff8ad8f7c0
RBP: ffffc90000007cb0 R08: dffffc0000000000 R09: fffffbfff1bd2a56
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000000f7c
R13: ffff88801ea59dc0 R14: ffffc90000007c30 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd582153000 CR3: 000000005c7f5000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:158 [inline]
 _raw_spin_unlock_irqrestore+0x75/0x130 kernel/locking/spinlock.c:194
 __run_hrtimer kernel/time/hrtimer.c:1682 [inline]
 __hrtimer_run_queues+0x48c/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 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:call_rcu+0x7aa/0xa70 kernel/rcu/tree.c:3088
Code: 3c 03 00 74 08 4c 89 f7 e8 73 ed 5e 00 f6 84 24 81 00 00 00 02 75 59 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <48> b8 00 00 00 00 00 fc ff df 4a c7 04 28 00 00 00 00 66 42 c7 44
RSP: 0000:ffffc90002ea75c0 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff920005d4ec8 RCX: ffffffff81631a88
RDX: dffffc0000000000 RSI: ffffffff8a8b2a20 RDI: ffffffff8ad8f7c0
RBP: ffffc90002ea76e0 R08: dffffc0000000000 R09: fffffbfff20e1e2c
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff1101720764c
R13: 1ffff920005d4ec4 R14: ffffc90002ea7640 R15: 0000000000000246
 __dentry_kill+0x436/0x650 fs/dcache.c:586
 shrink_dentry_list+0x398/0x6a0 fs/dcache.c:1181
 shrink_dcache_parent+0xc9/0x480
 do_one_tree+0x23/0xe0 fs/dcache.c:1662
 shrink_dcache_for_umount+0x79/0x120 fs/dcache.c:1679
 generic_shutdown_super+0x66/0x2c0 fs/super.c:447
 kill_anon_super+0x37/0x60 fs/super.c:1087
 proc_kill_sb+0x89/0xd0 fs/proc/root.c:275
 deactivate_locked_super+0xa0/0x110 fs/super.c:335
 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x6a3/0x2480 kernel/exit.c:874
 do_group_exit+0x144/0x310 kernel/exit.c:996
 get_signal+0xc66/0x14e0 kernel/signal.c:2897
 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe371a7cdaa
Code: Unable to access opcode bytes at RIP 0x7fe371a7cd80.
RSP: 002b:00007ffc6e662088 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fe371a7cdaa
RDX: 0000000000000060 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffc6e6620f0 R08: 0000000000000408 R09: 00007ffc6e662487
R10: 00007fe371be7630 R11: 0000000000000246 R12: 00007ffc6e66209c
R13: 0000555555621590 R14: 00000000000203c3 R15: 00007ffc6e6627c0
 </TASK>
rcu: rcu_preempt kthread starved for 10495 jiffies! g6713 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:27352 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 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: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: 21 Comm: kworker/1:0 Not tainted 5.15.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Workqueue: events fqdir_free_fn
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 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:1818
 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:1686 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 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_single+0x292/0x530 kernel/smp.c:758
Code: 0f 85 24 02 00 00 44 8b 6c 24 48 44 89 ee 83 e6 01 31 ff e8 c0 e4 0b 00 41 83 e5 01 75 0a e8 55 e1 0b 00 e9 eb 00 00 00 f3 90 <42> 0f b6 04 23 84 c0 75 15 f7 44 24 48 01 00 00 00 0f 84 cd 00 00
RSP: 0018:ffffc90000db7a60 EFLAGS: 00000293
RAX: ffffffff8174806e RBX: 1ffff920001b6f55 RCX: ffff888017e71dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000db7b50 R08: ffffffff81748040 R09: ffffed1017207679
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: 0000000000000001 R14: ffffc90000db7aa8 R15: 0000000000000000
 rcu_barrier+0x262/0x4e0 kernel/rcu/tree.c:4078
 fqdir_free_fn+0x2e/0x130 net/ipv4/inet_fragment.c:163
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/01 02:08 linux-5.15.y fa93fa65db6e 1eda0d14 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cleanup_mnt
2024/09/23 11:34 linux-5.15.y 3a5928702e71 89298aad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cleanup_mnt
2024/08/10 23:42 linux-5.15.y 7e89efd3ae1c 6f4edef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in cleanup_mnt
* Struck through repros no longer work on HEAD.