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BUG: KASAN: out-of-bounds in csd_lock_record+0xcb/0xe0 kernel/smp.c:118
Read of size 8 at addr ffffc900045678f0 by task syz-executor.5/19766

CPU: 1 PID: 19766 Comm: syz-executor.5 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:check_kcov_mode kernel/kcov.c:165 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2a/0x60 kernel/kcov.c:197
Code: 65 48 8b 14 25 c0 fe 01 00 65 8b 05 70 f7 8d 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 35 8b 82 0c 14 00 00 85 c0 74 2b <8b> 82 e8 13 00 00 83 f8 02 75 20 48 8b 8a f0 13 00 00 8b 92 ec 13
RSP: 0018:ffffc90001897788 EFLAGS: 00000246
RAX: 0000000080000001 RBX: 0000000000000001 RCX: ffffc90001897a58
RDX: ffff8880a7e5c000 RSI: ffffffff81a385c9 RDI: ffffc90001897a70
RBP: ffffc90001897a78 R08: 0000000000000000 R09: ffff8880a7e5c007
R10: 0000000000000000 R11: 0000000000000000 R12: 8000000055aff007
R13: ffffea000156bfc0 R14: dffffc0000000000 R15: 00007fce303d6000
 compound_head include/linux/page-flags.h:182 [inline]
 PageAnon include/linux/page-flags.h:475 [inline]
 zap_pte_range mm/memory.c:1079 [inline]
 zap_pmd_range mm/memory.c:1193 [inline]
 zap_pud_range mm/memory.c:1222 [inline]
 zap_p4d_range mm/memory.c:1243 [inline]
 unmap_page_range+0xca9/0x2b20 mm/memory.c:1264
 unmap_single_vma+0x198/0x300 mm/memory.c:1309
 unmap_vmas+0x16f/0x2f0 mm/memory.c:1341
 exit_mmap+0x2b1/0x530 mm/mmap.c:3165
 __mmput+0x122/0x470 kernel/fork.c:1075
 mmput+0x53/0x60 kernel/fork.c:1096
 exit_mm kernel/exit.c:483 [inline]
 do_exit+0xa8f/0x2a40 kernel/exit.c:793
 do_group_exit+0x125/0x310 kernel/exit.c:904
 get_signal+0x40b/0x1ee0 kernel/signal.c:2743
 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:218 [inline]
 __prepare_exit_to_usermode+0x156/0x1f0 arch/x86/entry/common.c:252
 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:376
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007fce2e833c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffea RBX: 00000000005035e0 RCX: 000000000045cb29
RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000005
RBP: 000000000078bf00 R08: 0000000000000398 R09: 0000000000000000
R10: 00000000200003c0 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a7d R14: 00000000004d6ee8 R15: 00007fce2e8346d4


Memory state around the buggy address:
 ffffc90004567780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004567800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004567880: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00
                                                             ^
 ffffc90004567900: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004567980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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