bisecting fixing commit since 88d6de67e390b6093f2c11189ad022988a9e2961
building syzkaller on c8e81ce4c7e3b59e7c83c6fab56c217916f3b3b6
testing commit 88d6de67e390b6093f2c11189ad022988a9e2961 with gcc (GCC) 8.1.0
kernel signature: 066e48a8a536c17beedd3c0165cb9fd2446763dd21c8c215e12cff67cc5f1735
all runs: crashed: KASAN: global-out-of-bounds Read in get_unique_tuple
testing current HEAD a39e75458e1ceb7fefaa3a0bd9df21558713cf0d
testing commit a39e75458e1ceb7fefaa3a0bd9df21558713cf0d with gcc (GCC) 8.1.0
kernel signature: 12a5e46d3279634626637136e369569f9af306c4aec9686e028cfaac3ef70531
all runs: crashed: KASAN: global-out-of-bounds Read in get_unique_tuple
revisions tested: 2, total time: 23m16.796323265s (build: 16m45.589735252s, test: 6m3.64757237s)
the crash still happens on HEAD
commit msg: Linux 4.19.130
crash: KASAN: global-out-of-bounds Read in get_unique_tuple
IPv6: ADDRCONF(NETDEV_UP): macvtap0: link is not ready
device veth0_macvtap entered promiscuous mode
IPv6: ADDRCONF(NETDEV_UP): macvtap0: link is not ready
==================================================================
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_macvtap: link becomes ready
BUG: KASAN: global-out-of-bounds in __read_once_size include/linux/compiler.h:193 [inline]
BUG: KASAN: global-out-of-bounds in __nf_nat_l4proto_find net/netfilter/nf_nat_core.c:73 [inline]
BUG: KASAN: global-out-of-bounds in get_unique_tuple+0x19d9/0x1eb0 net/netfilter/nf_nat_core.c:336
Read of size 8 at addr ffffffff87c50b20 by task syz-executor.4/7806

CPU: 1 PID: 7806 Comm: syz-executor.4 Not tainted 4.19.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x123/0x177 lib/dump_stack.c:118
 print_address_description.cold.8+0x58/0x1ff mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_macvtap: link becomes ready
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 __read_once_size include/linux/compiler.h:193 [inline]
 __nf_nat_l4proto_find net/netfilter/nf_nat_core.c:73 [inline]
 get_unique_tuple+0x19d9/0x1eb0 net/netfilter/nf_nat_core.c:336
IPv6: ADDRCONF(NETDEV_CHANGE): veth0_macvtap: link becomes ready
 nf_nat_setup_info+0x18a/0x730 net/netfilter/nf_nat_core.c:431
IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): macvtap0: link becomes ready
 __nf_nat_alloc_null_binding+0x109/0x1a0 net/netfilter/nf_nat_core.c:490
 nfnetlink_parse_nat_setup+0x2d3/0x340 net/netfilter/nf_nat_core.c:882
 ctnetlink_parse_nat_setup+0x7c/0x430 net/netfilter/nf_conntrack_netlink.c:1521
 ctnetlink_setup_nat net/netfilter/nf_conntrack_netlink.c:1591 [inline]
 ctnetlink_create_conntrack+0x389/0xfa0 net/netfilter/nf_conntrack_netlink.c:1984
 ctnetlink_new_conntrack+0x46c/0xe10 net/netfilter/nf_conntrack_netlink.c:2114
 nfnetlink_rcv_msg+0x942/0xc05 net/netfilter/nfnetlink.c:228
 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2455
 nfnetlink_rcv+0x163/0x3b0 net/netfilter/nfnetlink.c:560
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x443/0x650 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x765/0xc40 net/netlink/af_netlink.c:1909
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg+0xb5/0xf0 net/socket.c:632
 ___sys_sendmsg+0x647/0x950 net/socket.c:2115
 __sys_sendmsg+0xd9/0x180 net/socket.c:2153
 __do_sys_sendmsg net/socket.c:2162 [inline]
 __se_sys_sendmsg net/socket.c:2160 [inline]
 __x64_sys_sendmsg+0x73/0xb0 net/socket.c:2160
 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b349
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fce1e55bc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fce1e55c6d4 RCX: 000000000045b349
RDX: 0000000000000000 RSI: 0000000020000640 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000941 R14: 00000000004ca9f7 R15: 000000000075bf2c

The buggy address belongs to the variable:
 nft_rt_policy+0xa0/0xe0

Memory state around the buggy address:
 ffffffff87c50a00: 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa
 ffffffff87c50a80: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 03
>ffffffff87c50b00: fa fa fa fa 07 fa fa fa fa fa fa fa 00 00 00 00
                               ^
 ffffffff87c50b80: 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa
 ffffffff87c50c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa
==================================================================
batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!