bisecting fixing commit since 32ee7492f104d82b01a44fc4b4ae17d5d2bb237b building syzkaller on 93e5e33559b98e47f3743e6d907ca8444fbba5d4 testing commit 32ee7492f104d82b01a44fc4b4ae17d5d2bb237b with gcc (GCC) 8.1.0 kernel signature: 88a3f71fc0ea33c4f738809e4fbdbfe3307bacdc94ee80873392902c964ed4c8 all runs: crashed: KASAN: global-out-of-bounds Read in nfnetlink_parse_nat_setup testing current HEAD 3fc898571b974f9a05e4e5c1fe17b18548207091 testing commit 3fc898571b974f9a05e4e5c1fe17b18548207091 with gcc (GCC) 8.1.0 kernel signature: 77effa17d98b814a69feedcae365d1037048bf23b02f29009a0897cb4a4a8425 all runs: crashed: KASAN: global-out-of-bounds Read in nfnetlink_parse_nat_setup revisions tested: 2, total time: 23m26.315233075s (build: 16m53.549678182s, test: 6m6.353967156s) the crash still happens on HEAD commit msg: Linux 4.19.128 crash: KASAN: global-out-of-bounds Read in nfnetlink_parse_nat_setup batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! ================================================================== batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 BUG: KASAN: global-out-of-bounds in nfnetlink_parse_nat net/netfilter/nf_nat_core.c:847 [inline] BUG: KASAN: global-out-of-bounds in nfnetlink_parse_nat_setup+0x330/0x340 net/netfilter/nf_nat_core.c:884 Read of size 8 at addr ffffffff87c4c1d8 by task syz-executor.0/7836 CPU: 1 PID: 7836 Comm: syz-executor.0 Not tainted 4.19.128-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 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 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433 nfnetlink_parse_nat net/netfilter/nf_nat_core.c:847 [inline] nfnetlink_parse_nat_setup+0x330/0x340 net/netfilter/nf_nat_core.c:884 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 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 nfnetlink_rcv_msg+0x942/0xc05 net/netfilter/nfnetlink.c:228 netlink_rcv_skb+0x142/0x390 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 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:632 ___sys_sendmsg+0x647/0x950 net/socket.c:2115 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! __sys_sendmsg+0xd9/0x180 net/socket.c:2153 IPv6: ADDRCONF(NETDEV_UP): batadv_slave_0: link is not ready __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 batman_adv: batadv0: Interface activated: batadv_slave_0 entry_SYSCALL_64_after_hwframe+0x49/0xbe batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 RIP: 0033:0x45b399 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:00007f13a695ec78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f13a695f6d4 RCX: 000000000045b399 RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 R13: 00000000000008fd R14: 00000000004ca4bf R15: 000000000075bf2c The buggy address belongs to the variable: nft_immediate_policy+0xd8/0xe0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! Memory state around the buggy address: ffffffff87c4c080: 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa ffffffff87c4c100: 00 00 00 00 00 00 fa fa fa fa fa fa 00 00 00 00 >ffffffff87c4c180: 00 00 00 00 04 fa fa fa fa fa fa fa 00 00 00 00 ^ ffffffff87c4c200: 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 ffffffff87c4c280: 00 00 00 00 00 00 00 00 00 00 00 00 00 fa fa fa ==================================================================