syzbot


INFO: rcu detected stall in sys_unshare (5)

Status: closed as invalid on 2022/02/08 10:10
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 327d, last: 327d
similar bugs (5):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_unshare (2) 1 1064d 1064d 0/24 closed as invalid on 2020/01/08 05:23
upstream INFO: rcu detected stall in sys_unshare (3) 1 550d 550d 0/24 auto-closed as invalid on 2021/09/03 04:28
upstream INFO: rcu detected stall in sys_unshare (6) 1 296d 296d 0/24 auto-closed as invalid on 2022/05/15 15:21
upstream INFO: rcu detected stall in sys_unshare 3 1100d 1100d 0/24 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in sys_unshare (4) 1 459d 459d 0/24 auto-closed as invalid on 2021/12/03 09:38

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=14f/1/0x4000000000000000 softirq=158772/158773 fqs=2 
	(detected by 1, t=10502 jiffies, g=257157, q=36)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 18488 Comm: syz-executor.2 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:mark_usage kernel/locking/lockdep.c:4499 [inline]
RIP: 0010:__lock_acquire+0x1199/0x5470 kernel/locking/lockdep.c:4981
Code: ff 65 8b 05 21 11 a6 7e 85 c0 0f 85 0d 03 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5c 24 40 48 89 da 48 c1 ea 03 0f b6 14 02 <48> 89 d8 83 e0 07 83 c0 03 38 d0 7c 0c 84 d2 74 08 48 89 df e8 7e
RSP: 0018:ffffc90000007ad8 EFLAGS: 00000017
RAX: dffffc0000000000 RBX: ffff88802580e144 RCX: 1ffffffff1ff6bd6
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff8ffb5eb0
RBP: ffff88802580e1d2 R08: 0000000000000000 R09: ffffffff8ffb5a47
R10: 0000000000000001 R11: 0000000000000001 R12: ffff88802580e1b0
R13: ffff88802580d700 R14: ffff88802580e160 R15: dffffc0000000000
FS:  00007f949d303700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007eff17f25718 CR3: 0000000014982000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 lock_acquire kernel/locking/lockdep.c:5639 [inline]
 lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162
 debug_object_activate+0x12e/0x3e0 lib/debugobjects.c:661
 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline]
 debug_activate kernel/time/hrtimer.c:475 [inline]
 enqueue_hrtimer+0x27/0x3e0 kernel/time/hrtimer.c:1084
 __run_hrtimer kernel/time/hrtimer.c:1702 [inline]
 __hrtimer_run_queues+0xb02/0xe50 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:__memset+0x24/0x30 arch/x86/lib/memset_64.S:39
Code: cc cc cc cc cc cc 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 <f3> 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3
RSP: 0018:ffffc900029ffbf0 EFLAGS: 00000212
RAX: 0000000000000000 RBX: ffff88801d33e000 RCX: 0000000000000007
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffed1003a67cc8
RBP: 0000000000000800 R08: 0000000000000001 R09: ffffed1003a67c00
R10: 0000000000000001 R11: 0000000000000001 R12: ffff888010c42000
R13: 0000000000000dc0 R14: 0000000000000420 R15: 0000000000000dc0
 kasan_unpoison mm/kasan/shadow.c:138 [inline]
 kasan_unpoison+0x40/0x70 mm/kasan/shadow.c:115
 __kasan_slab_alloc+0x52/0xc0 mm/kasan/common.c:466
 kasan_slab_alloc include/linux/kasan.h:260 [inline]
 slab_post_alloc_hook mm/slab.h:738 [inline]
 slab_alloc_node mm/slub.c:3230 [inline]
 slab_alloc mm/slub.c:3238 [inline]
 __kmalloc+0x1e7/0x340 mm/slub.c:4420
 kmalloc include/linux/slab.h:587 [inline]
 kzalloc include/linux/slab.h:716 [inline]
 ops_init+0xfb/0x470 net/core/net_namespace.c:130
 setup_net+0x54f/0xbb0 net/core/net_namespace.c:328
 copy_net_ns+0x318/0x760 net/core/net_namespace.c:472
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3049
 __do_sys_unshare kernel/fork.c:3120 [inline]
 __se_sys_unshare kernel/fork.c:3118 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3118
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f949e98dfe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f949d303168 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007f949eaa0f60 RCX: 00007f949e98dfe9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000042000000
RBP: 00007f949e9e808d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fffabfd089f R14: 00007f949d303300 R15: 0000000000022000
 </TASK>
rcu: rcu_preempt kthread starved for 10498 jiffies! g257157 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:28328 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:4986 [inline]
 __schedule+0xab2/0x4f00 kernel/sched/core.c:6296
 schedule+0xd2/0x260 kernel/sched/core.c:6369
 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881
 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1963
 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2136
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 17264 Comm: kworker/u4:13 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound toggle_allocation_gate
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:458
 print_other_cpu_stall kernel/rcu/tree_stall.h:563 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:706 [inline]
 rcu_pending kernel/rcu/tree.c:3919 [inline]
 rcu_sched_clock_irq+0x1f7c/0x2150 kernel/rcu/tree.c:2617
 update_process_times+0x16d/0x200 kernel/time/timer.c:1785
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0x452/0xc20 kernel/smp.c:969
Code: 0b 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 f4 4c 89 f5 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 60 7c 0b 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 33 06 00 00 8b 43 08 31
RSP: 0018:ffffc9000296fa00 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b9c41ee0 RCX: 0000000000000000
RDX: ffff888017a23a00 RSI: ffffffff816c4e70 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000001
R10: ffffffff816c4e96 R11: 0000000000000000 R12: ffffed10173883dd
R13: 0000000000000000 R14: ffff8880b9c41ee8 R15: 0000000000000001
 on_each_cpu_cond_mask+0x56/0xa0 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+0x1b1/0x510 arch/x86/kernel/alternative.c:1300
 text_poke_flush arch/x86/kernel/alternative.c:1470 [inline]
 text_poke_flush arch/x86/kernel/alternative.c:1467 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1477
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x1da/0x400 kernel/jump_label.c:830
 static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177
 static_key_enable+0x16/0x20 kernel/jump_label.c:190
 toggle_allocation_gate mm/kfence/core.c:734 [inline]
 toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:726
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x405/0x4f0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
----------------
Code disassembly (best guess):
   0:	ff 65 8b             	jmpq   *-0x75(%rbp)
   3:	05 21 11 a6 7e       	add    $0x7ea61121,%eax
   8:	85 c0                	test   %eax,%eax
   a:	0f 85 0d 03 00 00    	jne    0x31d
  10:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  17:	fc ff df
  1a:	48 8b 5c 24 40       	mov    0x40(%rsp),%rbx
  1f:	48 89 da             	mov    %rbx,%rdx
  22:	48 c1 ea 03          	shr    $0x3,%rdx
  26:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx
* 2a:	48 89 d8             	mov    %rbx,%rax <-- trapping instruction
  2d:	83 e0 07             	and    $0x7,%eax
  30:	83 c0 03             	add    $0x3,%eax
  33:	38 d0                	cmp    %dl,%al
  35:	7c 0c                	jl     0x43
  37:	84 d2                	test   %dl,%dl
  39:	74 08                	je     0x43
  3b:	48 89 df             	mov    %rbx,%rdi
  3e:	e8                   	.byte 0xe8
  3f:	7e                   	.byte 0x7e

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2022/01/14 18:02 upstream fb3b0673b7d5 53e00b45 .config log report info INFO: rcu detected stall in sys_unshare
* Struck through repros no longer work on HEAD.