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INFO: rcu detected stall in sys_readlink

Status: auto-closed as invalid on 2022/07/22 05:22
Subsystems: fs
[Documentation on labels]
First crash: 734d, last: 734d
▶ ▼ Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_readlink (2) kernel 3 471d 530d 0/26 auto-obsoleted due to no activity on 2023/04/24 08:02
linux-5.15 INFO: rcu detected stall in sys_readlink 1 240d 240d 0/3 auto-obsoleted due to no activity on 2023/12/08 09:32
upstream INFO: rcu detected stall in sys_readlink (4) fs 2 145d 148d 0/26 auto-obsoleted due to no activity on 2024/03/02 18:22
upstream INFO: rcu detected stall in sys_readlink (3) bpf fs 2 346d 353d 0/26 auto-obsoleted due to no activity on 2023/08/14 04:05
android-5-15 BUG: soft lockup in sys_readlink 1 14d 14d 0/2 premoderation: reported on 2024/04/12 18:32

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P2963/1:b..l
	(detected by 1, t=10502 jiffies, g=148437, q=233)
task:udevd           state:R  running task     stack:22176 pid: 2963 ppid:     1 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5073 [inline]
 __schedule+0x939/0xea0 kernel/sched/core.c:6388
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6696
 irqentry_exit+0x56/0x90 kernel/entry/common.c:428
 asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:__legitimize_mnt+0x56/0x180 fs/namespace.c:632
Code: 49 bc 00 00 00 00 00 fc ff df 49 8d 5f 30 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 60 bd e9 ff 48 8b 03 65 ff 00 <f0> 83 44 24 fc 00 8b 1d 2e 20 94 0a 89 df 89 ee e8 95 d9 98 ff 39
RSP: 0018:ffffc90002baf960 EFLAGS: 00000206
RAX: 0000607f4620a014 RBX: ffff8880121dac50 RCX: 0000000000000000
RDX: ffff88807c5d8000 RSI: 000000000000e60e RDI: 000000000000e60e
RBP: 000000000000e60e R08: ffffffff81ed26d3 R09: ffffc90002baf920
R10: fffff52000575f2d R11: 1ffff92000575f24 R12: dffffc0000000000
R13: dffffc0000000000 R14: 0000000000000002 R15: ffff8880121dac20
 __legitimize_path fs/namei.c:691 [inline]
 legitimize_path fs/namei.c:708 [inline]
 try_to_unlazy+0x3ab/0xaa0 fs/namei.c:777
 may_lookup fs/namei.c:1734 [inline]
 link_path_walk+0x296/0xd80 fs/namei.c:2289
 path_lookupat+0xab/0x450 fs/namei.c:2498
 filename_lookup+0x277/0x640 fs/namei.c:2528
 user_path_at_empty+0x40/0x1a0 fs/namei.c:2851
 do_readlinkat+0x11b/0x3b0 fs/stat.c:456
 __do_sys_readlink fs/stat.c:489 [inline]
 __se_sys_readlink fs/stat.c:486 [inline]
 __x64_sys_readlink+0x7b/0x90 fs/stat.c:486
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7ff43cb27277
RSP: 002b:00007fff6b8f5df8 EFLAGS: 00000202 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007fff6b8f6618 RCX: 00007ff43cb27277
RDX: 0000000000000200 RSI: 00007fff6b8f5e08 RDI: 00007fff6b8f6008
RBP: 0000557280f1f910 R08: 0000000000000000 R09: 00007fff6b8f5ca0
R10: 00000000000019c0 R11: 0000000000000202 R12: 00007fff6b8f5e08
R13: 00007fff6b8f6008 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10219 jiffies! g148437 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:26424 pid:   16 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5073 [inline]
 __schedule+0x939/0xea0 kernel/sched/core.c:6388
 schedule+0xeb/0x1b0 kernel/sched/core.c:6460
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
 rcu_gp_fqs_loop+0x2b9/0xfb0 kernel/rcu/tree.c:1971
 rcu_gp_kthread+0xa5/0x360 kernel/rcu/tree.c:2144
 kthread+0x266/0x300 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G S                5.18.0-rc3-syzkaller-00190-gc00c5e1d157b #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+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x473/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x168/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_check_gp_kthread_starvation+0x1da/0x250 kernel/rcu/tree_stall.h:490
 print_other_cpu_stall+0x13fa/0x1550 kernel/rcu/tree_stall.h:595
 check_cpu_stall kernel/rcu/tree_stall.h:741 [inline]
 rcu_pending kernel/rcu/tree.c:3923 [inline]
 rcu_sched_clock_irq+0x928/0x18d0 kernel/rcu/tree.c:2625
 update_process_times+0x197/0x200 kernel/time/timer.c:1788
 tick_sched_handle kernel/time/tick-sched.c:243 [inline]
 tick_sched_timer+0x377/0x540 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3a6/0xfd0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0xf9/0x280 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:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:130 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:116 [inline]
RIP: 0010:acpi_idle_do_entry drivers/acpi/processor_idle.c:556 [inline]
RIP: 0010:acpi_idle_enter+0x42d/0x790 drivers/acpi/processor_idle.c:691
Code: fc 48 83 e3 08 44 8b 7c 24 04 0f 85 22 01 00 00 4c 8d 74 24 40 e8 93 fd 00 fd eb 0c e8 ac 59 fa fc 0f 00 2d f5 a1 68 06 fb f4 <4c> 89 f3 48 c1 eb 03 42 80 3c 23 00 74 08 4c 89 f7 e8 5d 3f 4b fd
RSP: 0018:ffffc90000d77c00 EFLAGS: 00000286
RAX: 6b78443496649d00 RBX: 0000000000000000 RCX: ffffffff90b7a603
RDX: dffffc0000000000 RSI: ffffffff8a8d0480 RDI: ffffffff8ae88c20
RBP: ffffc90000d77cb0 R08: ffffffff818ca320 R09: ffffed10024093b1
R10: ffffed10024093b1 R11: 1ffff110024093b0 R12: dffffc0000000000
R13: ffff8880115be064 R14: ffffc90000d77c40 R15: 0000000000000001
 cpuidle_enter_state+0x517/0xed0 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:236 [inline]
 do_idle+0x3d2/0x640 kernel/sched/idle.c:303
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:400
 secondary_startup_64_no_verify+0xc4/0xcb
 </TASK>
----------------
Code disassembly (best guess):
   0:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
   7:	fc ff df
   a:	49 8d 5f 30          	lea    0x30(%r15),%rbx
   e:	48 89 d8             	mov    %rbx,%rax
  11:	48 c1 e8 03          	shr    $0x3,%rax
  15:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1)
  1a:	74 08                	je     0x24
  1c:	48 89 df             	mov    %rbx,%rdi
  1f:	e8 60 bd e9 ff       	callq  0xffe9bd84
  24:	48 8b 03             	mov    (%rbx),%rax
  27:	65 ff 00             	incl   %gs:(%rax)
* 2a:	f0 83 44 24 fc 00    	lock addl $0x0,-0x4(%rsp) <-- trapping instruction
  30:	8b 1d 2e 20 94 0a    	mov    0xa94202e(%rip),%ebx        # 0xa942064
  36:	89 df                	mov    %ebx,%edi
  38:	89 ee                	mov    %ebp,%esi
  3a:	e8 95 d9 98 ff       	callq  0xff98d9d4
  3f:	39                   	.byte 0x39

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/04/23 05:14 upstream c00c5e1d157b 131df97d .config console log report info ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in sys_readlink
* Struck through repros no longer work on HEAD.