==================================================================
BUG: KASAN: out-of-bounds in csd_lock_record+0xcb/0xe0 kernel/smp.c:118
Read of size 8 at addr ffffc90004987550 by task syz-executor.3/27576

CPU: 1 PID: 27576 Comm: syz-executor.3 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:__find_rr_leaf+0x303/0xd10 net/ipv6/route.c:806
Code: e8 62 38 8e fa 48 8d bb 80 00 00 00 48 89 f8 48 c1 e8 03 0f b6 04 28 84 c0 74 08 3c 03 0f 8e d2 07 00 00 44 8b a3 80 00 00 00 <44> 8b 74 24 10 44 89 e7 44 89 f6 e8 2d 34 8e fa 45 39 f4 0f 85 fa
RSP: 0018:ffffc90004ed7440 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880974f9800 RCX: ffffc9000ff8e000
RDX: 0000000000040000 RSI: ffffffff86e5ce9e RDI: ffff8880974f9880
RBP: dffffc0000000000 R08: 0000000000000001 R09: ffffc90004ed7610
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000100
R13: ffffc90004ed7728 R14: 0000000000000000 R15: ffff8880953c26a0
 find_rr_leaf net/ipv6/route.c:858 [inline]
 rt6_select net/ipv6/route.c:902 [inline]
 fib6_table_lookup+0x5b3/0xa20 net/ipv6/route.c:2189
 ip6_pol_route+0x1e1/0x1190 net/ipv6/route.c:2225
 pol_lookup_func include/net/ip6_fib.h:583 [inline]
 fib6_rule_lookup+0x52a/0x6f0 net/ipv6/fib6_rules.c:119
 ip6_route_output_flags_noref+0x2c2/0x360 net/ipv6/route.c:2506
 ip6_route_output_flags+0x8b/0x310 net/ipv6/route.c:2519
 ip6_route_output include/net/ip6_route.h:98 [inline]
 ip6_dst_lookup_tail+0xb3a/0x1700 net/ipv6/ip6_output.c:1026
 ip6_dst_lookup_flow+0x8c/0x1d0 net/ipv6/ip6_output.c:1154
 ip6_datagram_dst_update+0x5fa/0xc80 net/ipv6/datagram.c:88
 __ip6_datagram_connect+0x5ee/0x1540 net/ipv6/datagram.c:247
 ip6_datagram_connect net/ipv6/datagram.c:271 [inline]
 ip6_datagram_connect_v6_only+0x6d/0xa0 net/ipv6/datagram.c:283
 inet_dgram_connect+0x14a/0x2d0 net/ipv4/af_inet.c:574
 __sys_connect_file+0x155/0x1a0 net/socket.c:1854
 __sys_connect+0x160/0x190 net/socket.c:1871
 __do_sys_connect net/socket.c:1882 [inline]
 __se_sys_connect net/socket.c:1879 [inline]
 __x64_sys_connect+0x6f/0xb0 net/socket.c:1879
 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:00007f9b072bbc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00000000004db920 RCX: 000000000045cb29
RDX: 000000000000001c RSI: 0000000020000040 RDI: 0000000000000003
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000008a R14: 00000000004c355e R15: 00007f9b072bc6d4


Memory state around the buggy address:
 ffffc90004987400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004987480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004987500: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 f3 f3 f3 f3
                                                 ^
 ffffc90004987580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004987600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================