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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 ffffc90008727530 by task syz-executor.0/5850

CPU: 0 PID: 5850 Comm: syz-executor.0 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:write_comp_data+0x2f/0x80 kernel/kcov.c:218
Code: 05 36 fc 8d 7e 65 48 8b 34 25 c0 fe 01 00 a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 0c 14 00 00 85 c0 74 4f 8b 86 e8 13 00 00 <83> f8 03 75 44 48 8b 86 f0 13 00 00 8b b6 ec 13 00 00 4c 8b 00 48
RSP: 0018:ffffc9000865efd0 EFLAGS: 00000246
RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff86cdc1c2
RDX: 0000000000000000 RSI: ffff888090fbe280 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88801a118170 R14: ffffc9000865f250 R15: dffffc0000000000
 ip_packet_match net/ipv4/netfilter/ip_tables.c:66 [inline]
 ipt_do_table+0x7b2/0x1860 net/ipv4/netfilter/ip_tables.c:284
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0xc5/0x1e0 net/netfilter/core.c:512
 nf_hook+0x2b8/0x540 include/linux/netfilter.h:262
 __ip_local_out+0x26e/0x530 net/ipv4/ip_output.c:114
 ip_local_out net/ipv4/ip_output.c:123 [inline]
 ip_send_skb+0x46/0x260 net/ipv4/ip_output.c:1566
 udp_send_skb+0x6cd/0x11a0 net/ipv4/udp.c:894
 udp_sendmsg+0x1c6b/0x26c0 net/ipv4/udp.c:1181
 udpv6_sendmsg+0x14dd/0x2b90 net/ipv6/udp.c:1286
 inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:638
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x331/0x810 net/socket.c:2352
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2406
 __sys_sendmmsg+0x195/0x480 net/socket.c:2496
 __do_sys_sendmmsg net/socket.c:2525 [inline]
 __se_sys_sendmmsg net/socket.c:2522 [inline]
 __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2522
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007fde4e9e6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00000000004fd760 RCX: 000000000045cb29
RDX: 0400000000000132 RSI: 0000000020004d80 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000004000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000903 R14: 00000000004cbe13 R15: 00007fde4e9e76d4


Memory state around the buggy address:
 ffffc90008727400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90008727480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90008727500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                     ^
 ffffc90008727580: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3
 ffffc90008727600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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