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INFO: rcu detected stall in d_walk

Status: fixed on 2018/07/09 18:05
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+ae80b790eb412884ca77@syzkaller.appspotmail.com
Fix commit: 4fb48871409e restore cond_resched() in shrink_dcache_parent()
First crash: 2366d, last: 2304d
▶ ▼ Duplicate bugs (7)
duplicates (7):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
BUG: soft lockup in _raw_spin_unlock fs C 72 2308d 2356d 0/28 closed as dup on 2018/04/23 08:40
INFO: rcu detected stall in vfs_rmdir fs 180 2304d 2365d 0/28 closed as dup on 2018/04/14 07:02
INFO: rcu detected stall in _raw_spin_unlock ext4 C 8720 2304d 2366d 0/28 closed as dup on 2018/04/14 07:02
INFO: rcu detected stall in shrink_dentry_list fs 29 2307d 2365d 0/28 closed as dup on 2018/04/14 09:45
INFO: rcu detected stall in shrink_dcache_parent fs C 11660 2304d 2366d 0/28 closed as dup on 2018/04/14 07:02
INFO: rcu detected stall in select_collect fs 435 2304d 2363d 0/28 closed as dup on 2018/04/16 09:11
INFO: rcu detected stall in do_raw_spin_unlock fs 271 2304d 2366d 0/28 closed as dup on 2018/04/14 07:02
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
INFO: rcu detected stall in d_walk 3 (4) 2018/09/04 08:18
[PATCH] fs/dcache.c: re-add cond_resched() in shrink_dcache_parent() 16 (16) 2018/04/16 18:28
▶ ▼ Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 INFO: rcu detected stall in d_walk 1 2223d 2223d 0/3 auto-closed as invalid on 2019/03/01 20:51

Sample crash report:
INFO: rcu_sched self-detected stall on CPU
	0-...!: (124999 ticks this GP) idle=e9e/1/4611686018427387906 softirq=20143/20143 fqs=0 
	 (t=125000 jiffies g=9955 c=9954 q=7)
rcu_sched kthread starved for 125000 jiffies! g9955 c9954 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
RCU grace-period kthread stack dump:
rcu_sched       R  running task    23896     9      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2859 [inline]
 __schedule+0x801/0x1e30 kernel/sched/core.c:3501
 schedule+0xef/0x430 kernel/sched/core.c:3545
 schedule_timeout+0x138/0x240 kernel/time/timer.c:1801
 rcu_gp_kthread+0x6b5/0x1940 kernel/rcu/tree.c:2231
 kthread+0x345/0x410 kernel/kthread.c:240
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
NMI backtrace for cpu 0
CPU: 0 PID: 4555 Comm: syz-executor826 Not tainted 4.17.0-rc6+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline]
 rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376
 print_cpu_stall kernel/rcu/tree.c:1525 [inline]
 check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593
 __rcu_pending kernel/rcu/tree.c:3356 [inline]
 rcu_pending kernel/rcu/tree.c:3401 [inline]
 rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763
 update_process_times+0x2d/0x70 kernel/time/timer.c:1636
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline]
 smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863
 </IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:783 [inline]
RIP: 0010:lock_acquire+0x257/0x520 kernel/locking/lockdep.c:3923
RSP: 0018:ffff8801ac7178f0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 1ffff100358e2f23 RCX: 0000000000000000
RDX: 1ffffffff11a31ad RSI: ffff8801d9332d78 RDI: 0000000000000286
RBP: ffff8801ac7179e0 R08: 0000000000000008 R09: 0000000000000004
R10: ffff8801d9332e18 R11: ffff8801d9332540 R12: ffff8801d9332540
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:246 [inline]
 rcu_read_lock include/linux/rcupdate.h:632 [inline]
 d_walk+0x49b/0xc80 fs/dcache.c:1303
 shrink_dcache_parent+0x179/0x230 fs/dcache.c:1486
 vfs_rmdir+0x202/0x470 fs/namei.c:3850
 do_rmdir+0x523/0x610 fs/namei.c:3911
 __do_sys_rmdir fs/namei.c:3929 [inline]
 __se_sys_rmdir fs/namei.c:3927 [inline]
 __x64_sys_rmdir+0x36/0x40 fs/namei.c:3927
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441437
RSP: 002b:00007ffc44f5bd88 EFLAGS: 00000207 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000441437
RDX: 0000000000000000 RSI: 00000000006cd858 RDI: 00007ffc44f5ce70
RBP: 00007ffc44f5ce70 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000005 R11: 0000000000000207 R12: 00000000014bd8a0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Crashes (25680):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/05/26 05:37 upstream 62d18ecfa641 f48c20b8 .config console log report syz C ci-upstream-kasan-gce-root
2018/05/20 01:40 upstream 0b449a441dac f48c20b8 .config console log report syz C ci-upstream-kasan-gce-root
2018/04/21 07:11 upstream 83beed7b2b26 ca03d688 .config console log report syz C ci-upstream-kasan-gce-root
2018/04/12 20:28 upstream c17b0aadb7d8 eb2295de .config console log report syz C ci-upstream-kasan-gce-root
2018/06/09 03:43 bpf-next 75d4e704fa8d 866118af .config console log report syz C ci-upstream-bpf-next-kasan-gce
2018/06/11 09:23 bpf-next 75d4e704fa8d 866118af .config console log report syz ci-upstream-bpf-next-kasan-gce
2018/05/18 19:21 upstream 3acf4e395260 849705db .config console log report ci-upstream-kasan-gce-root
2018/04/12 18:42 upstream c17b0aadb7d8 eb2295de .config console log report ci-upstream-kasan-gce-root
2018/06/13 22:40 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 21:40 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 21:33 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 20:32 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 19:07 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 18:20 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 17:00 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 16:21 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 15:12 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 14:38 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 13:32 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 12:25 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 11:41 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 10:34 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 10:07 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 09:06 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 08:15 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 07:11 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 06:50 bpf-next 75d4e704fa8d 27c5f59f .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 05:47 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 04:45 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 04:06 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 03:05 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 02:55 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 01:54 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/13 01:05 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 23:47 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 23:04 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 21:54 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 21:42 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 20:42 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 20:11 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 19:10 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 18:04 bpf-next 75d4e704fa8d 6dcbc435 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 17:22 bpf-next 75d4e704fa8d 598eb192 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 16:16 bpf-next 75d4e704fa8d 112eec79 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 13:42 bpf-next 75d4e704fa8d 112eec79 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 12:39 bpf-next 75d4e704fa8d 112eec79 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 11:13 bpf-next 75d4e704fa8d 112eec79 .config console log report ci-upstream-bpf-next-kasan-gce
2018/06/12 10:25 bpf-next 75d4e704fa8d 112eec79 .config console log report ci-upstream-bpf-next-kasan-gce
* Struck through repros no longer work on HEAD.