------------[ cut here ]------------
1
WARNING: kernel/rcu/tree_stall.h:1049 at rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049, CPU#1: syz.3.6214/28604
Modules linked in:
CPU: 1 UID: 0 PID: 28604 Comm: syz.3.6214 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:rcu_check_gp_start_stall.part.0+0x1c4/0x4b0 kernel/rcu/tree_stall.h:1049
Code: 88 61 01 00 00 be 04 00 00 00 48 c7 c7 40 23 19 9b e8 70 45 89 00 b8 01 00 00 00 87 05 25 ce 2b 19 85 c0 0f 85 3d 01 00 00 90 <0f> 0b 90 48 c7 c3 e4 4c d7 90 48 81 fd 40 09 7f 8e 74 5a 48 b8 00
RSP: 0018:ffffc900006a0de8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000002904 RCX: ffffffff81ed5510
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff9b192340
RBP: ffffffff8e7f0940 R08: 0000000000000001 R09: fffffbfff3632468
R10: 0000000000000003 R11: 0000000000000000 R12: 1ffffffff1c81e50
R13: 0000000000000246 R14: 0000000000000004 R15: 0000000000000001
FS:  00007f9d52b8e6c0(0000) GS:ffff8880d6487000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30223ffc CR3: 000000005dbf7000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 rcu_check_gp_start_stall kernel/rcu/tree_stall.h:1012 [inline]
 rcu_core+0x2cb/0x10d0 kernel/rcu/tree.c:2864
 handle_softirqs+0x1ea/0xa00 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
 sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1061
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x58e/0x1700 kernel/smp.c:892
Code: 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 a9 83 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31 ff 83 e0 01 41
RSP: 0018:ffffc9000654fb40 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffc9000d2f1000
RDX: 0000000000080000 RSI: ffffffff81fc2dd7 RDI: ffff888047cc2540
RBP: ffff88806a643400 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed100d4c8681 R14: 0000000000000001 R15: ffff88806a53c800
 clock_was_set+0x62b/0x870 kernel/time/hrtimer.c:999
 do_settimeofday64+0x330/0x4d0 kernel/time/timekeeping.c:1603
 do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195
 __do_sys_clock_settime kernel/time/posix-timers.c:1124 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1108 [inline]
 __x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1108
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9d51d9ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9d52b8e028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007f9d52015fa0 RCX: 00007f9d51d9ce59
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007f9d51e32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9d52016038 R14: 00007f9d52015fa0 R15: 00007ffcd6bc6058
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 fc                	add    %bh,%ah
   2:	ff                   	lcall  (bad)
   3:	df 48 8b             	fisttps -0x75(%rax)
   6:	54                   	push   %rsp
   7:	24 08                	and    $0x8,%al
   9:	49 89 d5             	mov    %rdx,%r13
   c:	49 89 d4             	mov    %rdx,%r12
   f:	49 c1 ed 03          	shr    $0x3,%r13
  13:	41 83 e4 07          	and    $0x7,%r12d
  17:	49 01 c5             	add    %rax,%r13
  1a:	41 83 c4 03          	add    $0x3,%r12d
  1e:	e8 a9 83 0c 00       	call   0xc83cc
  23:	f3 90                	pause
  25:	41 0f b6 45 00       	movzbl 0x0(%r13),%eax
* 2a:	41 38 c4             	cmp    %al,%r12b <-- trapping instruction
  2d:	7c 08                	jl     0x37
  2f:	84 c0                	test   %al,%al
  31:	0f 85 63 0f 00 00    	jne    0xf9a
  37:	8b 45 08             	mov    0x8(%rbp),%eax
  3a:	31 ff                	xor    %edi,%edi
  3c:	83 e0 01             	and    $0x1,%eax
  3f:	41                   	rex.B