==================================================================
BUG: KASAN: out-of-bounds in csd_lock_record+0xcb/0xe0 kernel/smp.c:118
Read of size 8 at addr ffffc90003cd7950 by task syz-fuzzer/6786

CPU: 1 PID: 6786 Comm: syz-fuzzer Not tainted 5.8.0-rc3-next-20200703-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0x5/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 csd_lock_record+0xcb/0xe0 kernel/smp.c:118
 flush_smp_call_function_queue+0x285/0x730 kernel/smp.c:391
 __sysvec_call_function_single+0x98/0x490 arch/x86/kernel/smp.c:248
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_call_function_single+0xe0/0x120 arch/x86/kernel/smp.c:243
 asm_sysvec_call_function_single+0x12/0x20 arch/x86/include/asm/idtentry.h:604
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x4b/0x80 kernel/locking/spinlock.c:199
Code: c0 10 ff b4 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d ee 7a c8 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 db 01 63 f9 65 8b 05 44 7a 15 78 85 c0 74 02 5d
RSP: 0018:ffffc900010778a0 EFLAGS: 00000286
RAX: 1ffffffff1369fe2 RBX: ffff888094cee580 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffffff87ec83ff
RBP: ffff8880ae735e00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880ae735e00
R13: ffff888094460580 R14: 0000000000000000 R15: 0000000000000001
 finish_lock_switch kernel/sched/core.c:3184 [inline]
 finish_task_switch+0x147/0x750 kernel/sched/core.c:3284
 context_switch kernel/sched/core.c:3448 [inline]
 __schedule+0x8bc/0x1e80 kernel/sched/core.c:4169
 schedule+0xd0/0x2a0 kernel/sched/core.c:4244
 freezable_schedule include/linux/freezer.h:172 [inline]
 futex_wait_queue_me+0x2a7/0x570 kernel/futex.c:2634
 futex_wait+0x1df/0x560 kernel/futex.c:2740
 do_futex+0x15b/0x1a60 kernel/futex.c:3811
 __do_sys_futex kernel/futex.c:3872 [inline]
 __se_sys_futex kernel/futex.c:3840 [inline]
 __x64_sys_futex+0x378/0x4e0 kernel/futex.c:3840
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x460c23
Code: Bad RIP value.
RSP: 002b:00007ffce747dbe8 EFLAGS: 00000286 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00000000017004e0 RCX: 0000000000460c23
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000001700628
RBP: 00007ffce747dc30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000286 R12: 000001c1a4ea438a
R13: 0000000000000001 R14: 000001c1a4ea438a R15: 00000000000000ff


Memory state around the buggy address:
 ffffc90003cd7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003cd7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90003cd7900: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3
                                                 ^
 ffffc90003cd7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90003cd7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================