syzbot


INFO: rcu detected stall in do_faccessat (5)

Status: auto-closed as invalid on 2022/02/07 01:08
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 413d, last: 392d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in do_faccessat (4) 1 495d 495d 0/24 auto-closed as invalid on 2021/09/26 22:47
upstream INFO: rcu detected stall in do_faccessat (2) 1 811d 811d 0/24 auto-closed as invalid on 2020/12/14 19:23
upstream INFO: rcu detected stall in do_faccessat (3) 1 714d 714d 0/24 auto-closed as invalid on 2021/03/21 19:47
upstream INFO: rcu detected stall in do_faccessat 1 909d 909d 0/24 auto-closed as invalid on 2020/09/07 18:08

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=2b3/1/0x4000000000000000 softirq=170187/170188 fqs=2393 
	(detected by 1, t=10502 jiffies, g=295413, q=928)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 2938 Comm: systemd-udevd Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:rcu_lockdep_current_cpu_online+0xf4/0x130
Code: 23 75 27 49 83 c6 78 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 09 65 61 00 49 f7 06 01 00 00 00 75 04 31 c0 eb 02 <b0> 01 65 ff 0d 9b c2 93 7e 74 08 5b 41 5c 41 5e 41 5f c3 0f 1f 44
RSP: 0018:ffffc90000007a38 EFLAGS: 00000002
RAX: 1ffffffff1964376 RBX: ffffffff8cb21bb0 RCX: 0000000000010003
RDX: 0000000000000000 RSI: 0000000000010004 RDI: ffff8880b9a3a418
RBP: ffffc90000007af0 R08: dffffc0000000000 R09: fffffbfff1bfa646
R10: fffffbfff1bfa646 R11: 0000000000000000 R12: 0000000000000001
R13: 1ffff92000000f70 R14: ffffffff8cb21b40 R15: dffffc0000000000
FS:  00007fd62dbb48c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7d3e0cf004 CR3: 00000000149d0000 CR4: 00000000003506f0
DR0: 0000800000000002 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_read_lock_held_common kernel/rcu/update.c:112 [inline]
 rcu_read_lock_sched_held+0x74/0x130 kernel/rcu/update.c:123
 trace_lock_release+0x4f/0x150 include/trace/events/lock.h:58
 lock_release+0x82/0x810 kernel/locking/lockdep.c:5651
 __raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
 _raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:390 [inline]
 advance_sched+0x68b/0x930 net/sched/sch_taprio.c:759
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x50b/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_is_held_type+0x63/0x190 kernel/locking/lockdep.c:5679
Code: fd 00 00 00 65 4c 8b 2c 25 c0 6f 02 00 41 83 bd 5c 0a 00 00 00 0f 85 e6 00 00 00 41 89 f6 49 89 ff 48 c7 04 24 00 00 00 00 9c <8f> 04 24 4c 8b 24 24 fa 48 c7 c7 00 0c 6f 8a e8 79 11 00 00 65 ff
RSP: 0018:ffffc90001b6f510 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000080000001
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8cb1d860
RBP: ffffc90001b6f5f0 R08: dffffc0000000000 R09: fffffbfff1bfa646
R10: fffffbfff1bfa646 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888018b18000 R14: 00000000ffffffff R15: ffffffff8cb1d860
 lock_is_held include/linux/lockdep.h:283 [inline]
 rcu_read_lock_sched_held+0x89/0x130 kernel/rcu/update.c:125
 trace_lock_release+0x4f/0x150 include/trace/events/lock.h:58
 lock_release+0x82/0x810 kernel/locking/lockdep.c:5651
 rcu_read_unlock include/linux/rcupdate.h:721 [inline]
 lookup_mnt+0x2c7/0x2e0 fs/namespace.c:663
 __traverse_mounts fs/namei.c:1338 [inline]
 traverse_mounts+0x235/0x690 fs/namei.c:1385
 handle_mounts fs/namei.c:1494 [inline]
 step_into+0x1e0/0x1f90 fs/namei.c:1800
 walk_component+0x33a/0x790 fs/namei.c:1976
 link_path_walk+0x697/0xd00
 path_lookupat+0xab/0x6c0 fs/namei.c:2448
 filename_lookup+0x270/0x640 fs/namei.c:2478
 user_path_at_empty+0x40/0x1a0 fs/namei.c:2801
 user_path_at include/linux/namei.h:57 [inline]
 do_faccessat+0x43f/0x940 fs/open.c:421
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fd62ca269c7
Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe9993d498 EFLAGS: 00000246 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 0000564b7a13bd20 RCX: 00007fd62ca269c7
RDX: 00746e657665752f RSI: 0000000000000000 RDI: 00007ffe9993d4a0
RBP: 00007ffe9993d520 R08: 000000000000fc00 R09: 0000000000001010
R10: 0000000000000020 R11: 0000000000000246 R12: 0000564b786d5856
R13: 0000564b7a140cf0 R14: 00007ffe9993d4a0 R15: 0000564b7a12cde0
 </TASK>
rcu: rcu_preempt kthread starved for 5467 jiffies! g295413 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:26576 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4969 [inline]
 __schedule+0xb72/0x1460 kernel/sched/core.c:6250
 schedule+0x12b/0x1f0 kernel/sched/core.c:6323
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881
 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1955
 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2128
 kthread+0x468/0x490 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 8950 Comm: syz-executor.5 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481
 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:729 [inline]
 rcu_pending kernel/rcu/tree.c:3878 [inline]
 rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2597
 update_process_times+0x197/0x200 kernel/time/timer.c:1785
 tick_sched_handle kernel/time/tick-sched.c:226 [inline]
 tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xbb2/0xda0 kernel/smp.c:969
Code: 83 e6 01 31 ff e8 be b7 0b 00 41 83 e7 01 49 bf 00 00 00 00 00 fc ff df 75 0e e8 99 b3 0b 00 eb 4c 0f 1f 80 00 00 00 00 f3 90 <42> 0f b6 04 3b 84 c0 75 11 41 f7 45 00 01 00 00 00 74 2b e8 76 b3
RSP: 0018:ffffc90002cef380 EFLAGS: 00000293
RAX: ffffffff817898ea RBX: 1ffff11017348315 RCX: ffff88801c3b5700
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002cef4c0 R08: ffffffff817898b2 R09: ffffffff843959c0
R10: 0000000000000009 R11: ffff88801c3b5700 R12: 0000000000000000
R13: ffff8880b9a418a8 R14: ffff8880b9b3a600 R15: dffffc0000000000
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:1112 [inline]
 text_poke_bp_batch+0x310/0x940 arch/x86/kernel/alternative.c:1297
 text_poke_flush arch/x86/kernel/alternative.c:1451 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1458
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 static_key_disable_cpuslocked+0xcc/0x1b0 kernel/jump_label.c:207
 static_key_disable+0x16/0x20 kernel/jump_label.c:215
 tracepoint_remove_func kernel/tracepoint.c:417 [inline]
 tracepoint_probe_unregister+0x730/0x9c0 kernel/tracepoint.c:551
 trace_event_reg+0x215/0x250
 perf_trace_event_unreg+0xaf/0x220 kernel/trace/trace_event_perf.c:162
 perf_trace_destroy+0x93/0xb0 kernel/trace/trace_event_perf.c:243
 _free_event+0x874/0xe50 kernel/events/core.c:4982
 put_event kernel/events/core.c:5076 [inline]
 perf_event_release_kernel+0x86f/0x900 kernel/events/core.c:5191
 perf_release+0x37/0x40 kernel/events/core.c:5201
 __fput+0x3fc/0x870 fs/file_table.c:280
 task_work_run+0x146/0x1c0 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x705/0x24f0 kernel/exit.c:832
 do_group_exit+0x168/0x2d0 kernel/exit.c:929
 get_signal+0x16b0/0x2090 kernel/signal.c:2820
 arch_do_signal_or_restart+0x9c/0x730 arch/x86/kernel/signal.c:868
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x191/0x220 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:300
 do_syscall_64+0x53/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f7bf4075ae9
Code: Unable to access opcode bytes at RIP 0x7f7bf4075abf.
RSP: 002b:00007f7bf15eb218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007f7bf4188f68 RCX: 00007f7bf4075ae9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f7bf4188f68
RBP: 00007f7bf4188f60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7bf4188f6c
R13: 00007ffed1193a5f R14: 00007f7bf15eb300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess):
   0:	23 75 27             	and    0x27(%rbp),%esi
   3:	49 83 c6 78          	add    $0x78,%r14
   7:	4c 89 f0             	mov    %r14,%rax
   a:	48 c1 e8 03          	shr    $0x3,%rax
   e:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1)
  13:	74 08                	je     0x1d
  15:	4c 89 f7             	mov    %r14,%rdi
  18:	e8 09 65 61 00       	callq  0x616526
  1d:	49 f7 06 01 00 00 00 	testq  $0x1,(%r14)
  24:	75 04                	jne    0x2a
  26:	31 c0                	xor    %eax,%eax
  28:	eb 02                	jmp    0x2c
* 2a:	b0 01                	mov    $0x1,%al <-- trapping instruction
  2c:	65 ff 0d 9b c2 93 7e 	decl   %gs:0x7e93c29b(%rip)        # 0x7e93c2ce
  33:	74 08                	je     0x3d
  35:	5b                   	pop    %rbx
  36:	41 5c                	pop    %r12
  38:	41 5e                	pop    %r14
  3a:	41 5f                	pop    %r15
  3c:	c3                   	retq
  3d:	0f                   	.byte 0xf
  3e:	1f                   	(bad)
  3f:	44                   	rex.R

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/11/09 01:03 upstream e851dfae4371 8ab17e57 .config log report info INFO: rcu detected stall in do_faccessat
ci-upstream-linux-next-kasan-gce-root 2021/10/19 05:38 linux-next 60e8840126bd 24dc29db .config log report info INFO: rcu detected stall in do_faccessat
* Struck through repros no longer work on HEAD.