syzbot


INFO: rcu detected stall in recvmsg

Status: auto-closed as invalid on 2021/11/26 18:06
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 468d, last: 456d
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in recvmsg (2) 1 216d 216d 0/24 auto-closed as invalid on 2022/06/24 23:42

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=573877, q=279)
rcu: All QSes seen, last rcu_preempt kthread activity 10500 (4295299232-4295288732), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10500 jiffies! g573877 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:28864 pid:   14 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:4683 [inline]
 __schedule+0x93a/0x26f0 kernel/sched/core.c:5940
 schedule+0xd3/0x270 kernel/sched/core.c:6019
 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline]
 rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 30478 Comm: syz-executor.5 Not tainted 5.14.0-rc4-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+0xcd/0x134 lib/dump_stack.c:105
 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105
 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+0x1d1/0x1d6 kernel/rcu/tree_stall.h:479
 print_other_cpu_stall kernel/rcu/tree_stall.h:584 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:709 [inline]
 rcu_pending kernel/rcu/tree.c:3922 [inline]
 rcu_sched_clock_irq+0x2001/0x20c0 kernel/rcu/tree.c:2641
 update_process_times+0x16d/0x200 kernel/time/timer.c:1783
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421
 __run_hrtimer kernel/time/hrtimer.c:1537 [inline]
 __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601
 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1100
 </IRQ>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:434 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x3ba/0xb40 kernel/locking/qspinlock.c:508
Code: eb c6 45 01 01 41 bc 00 80 00 00 48 c1 e9 03 83 e3 07 41 be 01 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 2c 01 eb 0c f3 90 <41> 83 ec 01 0f 84 72 04 00 00 41 0f b6 45 00 38 d8 7f 08 84 c0 0f
RSP: 0018:ffffc9000b6e7000 EFLAGS: 00000206
RAX: 0000000000000003 RBX: 0000000000000000 RCX: 1ffff11010be2b5c
RDX: 0000000000000001 RSI: ffffffff817bcf01 RDI: ffffffff81332591
RBP: ffff888085f15ae0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff817bcec9 R11: 0000000000000000 R12: 0000000000002a09
R13: ffffed1010be2b5c R14: 0000000000000001 R15: ffff8880b9c52880
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock+0x200/0x2b0 kernel/locking/spinlock_debug.c:113
 spin_lock include/linux/spinlock.h:354 [inline]
 wp_page_copy+0x63a/0x2450 mm/memory.c:3036
 do_wp_page+0x2cb/0x1ad0 mm/memory.c:3313
 handle_pte_fault mm/memory.c:4576 [inline]
 __handle_mm_fault+0x2ada/0x5320 mm/memory.c:4693
 handle_mm_fault+0x1c8/0x790 mm/memory.c:4791
 do_user_addr_fault+0x48b/0x11c0 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0010:copy_user_enhanced_fast_string+0xe/0x40 arch/x86/lib/copy_user_64.S:206
Code: 89 d1 c1 e9 03 83 e2 07 f3 48 a5 89 d1 f3 a4 31 c0 0f 1f 00 c3 0f 1f 80 00 00 00 00 0f 1f 00 83 fa 40 0f 82 70 ff ff ff 89 d1 <f3> a4 31 c0 0f 1f 00 c3 66 2e 0f 1f 84 00 00 00 00 00 89 d1 83 f8
RSP: 0018:ffffc9000b6e75f0 EFLAGS: 00010206
RAX: 0000000000000001 RBX: 0000000000008000 RCX: 0000000000004500
RDX: 0000000000008000 RSI: ffff8880a2d9bb00 RDI: 00000000202fb000
RBP: 00000000202f7500 R08: 0000000000000000 R09: ffff8880a2d9ffff
R10: ffffed10145b3fff R11: 0000000000000000 R12: ffff8880a2d98000
R13: 00000000202ff500 R14: 0000000000000000 R15: ffffc9000b6e7d38
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 copyout.part.0+0xe4/0x110 lib/iov_iter.c:157
 copyout lib/iov_iter.c:620 [inline]
 _copy_to_iter+0x2b1/0x1600 lib/iov_iter.c:620
 copy_to_iter include/linux/uio.h:139 [inline]
 simple_copy_to_iter+0x4c/0x70 net/core/datagram.c:519
 __skb_datagram_iter+0x4a7/0x770 net/core/datagram.c:448
 skb_copy_datagram_iter+0x40/0x50 net/core/datagram.c:533
 skb_copy_datagram_msg include/linux/skbuff.h:3615 [inline]
 unix_stream_read_actor+0x78/0xc0 net/unix/af_unix.c:2502
 unix_stream_read_generic+0x782/0x19e0 net/unix/af_unix.c:2421
 unix_stream_recvmsg+0xb1/0xf0 net/unix/af_unix.c:2518
 sock_recvmsg_nosec net/socket.c:943 [inline]
 sock_recvmsg net/socket.c:961 [inline]
 sock_recvmsg net/socket.c:957 [inline]
 ____sys_recvmsg+0x2c4/0x600 net/socket.c:2611
 ___sys_recvmsg+0x127/0x200 net/socket.c:2653
 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2683
 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: 0033:0x4665e9
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:00007fad72963188 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000003f9c RSI: 0000000020000200 RDI: 0000000000000004
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffcb420b3cf R14: 00007fad72963300 R15: 0000000000022000
----------------
Code disassembly (best guess):
   0:	eb c6                	jmp    0xffffffc8
   2:	45 01 01             	add    %r8d,(%r9)
   5:	41 bc 00 80 00 00    	mov    $0x8000,%r12d
   b:	48 c1 e9 03          	shr    $0x3,%rcx
   f:	83 e3 07             	and    $0x7,%ebx
  12:	41 be 01 00 00 00    	mov    $0x1,%r14d
  18:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1f:	fc ff df 
  22:	4c 8d 2c 01          	lea    (%rcx,%rax,1),%r13
  26:	eb 0c                	jmp    0x34
  28:	f3 90                	pause  
  2a:	41 83 ec 01          	sub    $0x1,%r12d <-- trapping instruction
  2e:	0f 84 72 04 00 00    	je     0x4a6
  34:	41 0f b6 45 00       	movzbl 0x0(%r13),%eax
  39:	38 d8                	cmp    %bl,%al
  3b:	7f 08                	jg     0x45
  3d:	84 c0                	test   %al,%al
  3f:	0f                   	.byte 0xf

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-bpf-kasan-gce 2021/08/17 06:02 bpf 3776f3517ed9 33c26cb7 .config log report info INFO: rcu detected stall in recvmsg
ci-upstream-bpf-next-kasan-gce 2021/08/28 18:02 bpf-next 47bb27a20d6e be2c130d .config log report info INFO: rcu detected stall in recvmsg
ci-upstream-bpf-next-kasan-gce 2021/08/27 23:50 bpf-next 47bb27a20d6e d5a29e53 .config log report info INFO: rcu detected stall in recvmsg
* Struck through repros no longer work on HEAD.