==================================================================
BUG: KASAN: stack-out-of-bounds in user_mode arch/x86/include/asm/ptrace.h:131 [inline]
BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x10a0/0x1400 arch/x86/kernel/unwind_orc.c:410
Read of size 8 at addr ffff88804c7ffa60 by task syz-executor.0/7523

CPU: 0 PID: 7523 Comm: syz-executor.0 Not tainted 4.19.211-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:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 user_mode arch/x86/include/asm/ptrace.h:131 [inline]
 unwind_next_frame+0x10a0/0x1400 arch/x86/kernel/unwind_orc.c:410
 __save_stack_trace+0x9f/0x190 arch/x86/kernel/stacktrace.c:44
 save_stack mm/kasan/kasan.c:448 [inline]
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x126/0x1f0 mm/kasan/kasan.c:521
 __cache_free mm/slab.c:3503 [inline]
 kmem_cache_free+0x7f/0x260 mm/slab.c:3765
 __rcu_reclaim kernel/rcu/rcu.h:236 [inline]
 rcu_do_batch kernel/rcu/tree.c:2584 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
 rcu_process_callbacks+0x8ff/0x18b0 kernel/rcu/tree.c:2881
 __do_softirq+0x265/0x980 kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x215/0x260 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
 </IRQ>
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:784 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:806 [inline]
RIP: 0010:lock_is_held_type+0x81/0x210 kernel/locking/lockdep.c:3942
Code: 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 6a 01 00 00 48 83 3d 36 cd a6 08 00 0f 84 1d 01 00 00 9c <58> 0f 1f 44 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 c3 48 c7 c0
RSP: 0018:ffff88804c7ff880 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13e3050 RBX: ffff8880a3310180 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 00000000ffffffff RDI: ffff8880a3310a04
RBP: ffffffff89f85f20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000000 R12: ffffffff813f6735
R13: ffff88804c7ff9a8 R14: ffff88809714db28 R15: ffff88804c7ffa40
 __kthread_create_on_node+0x305/0x410 kernel/kthread.c:356
 retint_kernel+0x2d/0x2d
RIP: 0001:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline]
RIP: 0001:lock_acquire+0x1ec/0x3c0 kernel/locking/lockdep.c:3911
Code: Bad RIP value.
RSP: 0018:ffff88804c7ffa80 EFLAGS: 00000286 ORIG_RAX: ffff88804c7ffaa0
RAX: ffffffff89b7079d RBX: ffff888033506fc0 RCX: ffffffff813f6840
RDX: dffffc0000000000 RSI: 0000000000000028 RDI: ffff88804c7ffb08
RBP: ffffffff8626dbd0 R08: 0000000041b58ab3 R09: ffffffff813f68fb
R10: ffffffff893d1920 R11: 00000000ffffffff R12: ffff88804c7ffaf8
R13: ffffed10098fff44 R14: aa6e9473a9169000 R15: 0000000000000001

The buggy address belongs to the page:
page:ffffea000131ffc0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfff00000000000()
raw: 00fff00000000000 0000000000000000 ffffffff01310101 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88804c7ff900: 00 f1 f1 f1 f1 f1 f1 00 00 00 00 00 00 00 00 00
 ffff88804c7ff980: 00 f2 f2 f2 f2 00 00 f3 f3 00 00 00 00 00 00 00
>ffff88804c7ffa00: 00 00 00 00 f1 f1 f1 f1 00 00 00 f3 f3 f3 f3 f3
                                                       ^
 ffff88804c7ffa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804c7ffb00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
==================================================================
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
   7:	fc ff df
   a:	48 c1 e8 03          	shr    $0x3,%rax
   e:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1)
  12:	0f 85 6a 01 00 00    	jne    0x182
  18:	48 83 3d 36 cd a6 08 	cmpq   $0x0,0x8a6cd36(%rip)        # 0x8a6cd56
  1f:	00
  20:	0f 84 1d 01 00 00    	je     0x143
  26:	9c                   	pushfq
* 27:	58                   	pop    %rax <-- trapping instruction
  28:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  2d:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  34:	fc ff df
  37:	48 89 c3             	mov    %rax,%rbx
  3a:	48                   	rex.W
  3b:	c7                   	.byte 0xc7
  3c:	c0                   	.byte 0xc0