bisecting fixing commit since 32ee7492f104d82b01a44fc4b4ae17d5d2bb237b building syzkaller on 93e5e33559b98e47f3743e6d907ca8444fbba5d4 testing commit 32ee7492f104d82b01a44fc4b4ae17d5d2bb237b with gcc (GCC) 8.1.0 kernel signature: b0621e9a16e48abe193472a98c54cf893f24d1444930216561fbb6fb50412805 all runs: crashed: general protection fault in nft_rhash_insert testing current HEAD a083db76118d20d070794ecf79af17843406c3f6 testing commit a083db76118d20d070794ecf79af17843406c3f6 with gcc (GCC) 8.1.0 kernel signature: 91c4c1efe7f351dd915090ca7e8895c8c852d08968bec810ae799da5618839c0 all runs: crashed: general protection fault in nft_rhash_insert revisions tested: 2, total time: 25m36.287185817s (build: 18m7.247369486s, test: 6m49.186502214s) the crash still happens on HEAD commit msg: Linux 4.19.107 crash: general protection fault in nft_rhash_insert audit: type=1400 audit(1583348967.360:41): avc: denied { write } for pid=7464 comm="syz-executor.2" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_netfilter_socket permissive=1 kasan: GPF could be caused by NULL-ptr deref or user memory access batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! general protection fault: 0000 [#1] PREEMPT SMP KASAN batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 CPU: 1 PID: 7465 Comm: syz-executor.2 Not tainted 4.19.107-syzkaller #0 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:nft_rhash_insert+0x87/0xe60 net/netfilter/nft_set_hash.c:166 Code: 4c 89 b5 60 ff ff ff c7 01 f1 f1 f1 f1 c7 41 04 00 00 00 f2 65 48 8b 0c 25 28 00 00 00 48 89 4d d0 31 c9 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f 85 96 0b 00 00 48 8b 42 40 49 8d bd c4 18 00 00 49 RSP: 0018:ffff8880a3727038 EFLAGS: 00010203 RAX: dffffc0000000000 RBX: ffff8880a3727168 RCX: 03fffffffe248e02 RDX: 1ffffffff1246fd6 RSI: ffff8880a3727168 RDI: 1ffffffff1247016 RBP: ffff8880a3727120 R08: dffffc0000000000 R09: 0000000000000001 R10: ffffed10146e4e3e R11: ffff8880a37271f7 R12: ffff8880a37270f8 R13: ffff8880a37271c8 R14: 1ffff110146e4e13 R15: ffff8880a3727228 FS: 00007fa5b0c6e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000758080 CR3: 00000000a475f000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: nfnetlink_parse_nat net/netfilter/nf_nat_core.c:847 [inline] nfnetlink_parse_nat_setup+0x1ee/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:1596 [inline] ctnetlink_create_conntrack+0x3be/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+0x142/0x390 net/netlink/af_netlink.c:2454 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 nfnetlink_rcv+0x163/0x3b0 net/netfilter/nfnetlink.c:560 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x443/0x650 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x765/0xc40 net/netlink/af_netlink.c:1908 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 __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: 0033:0x45b399 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:00007fa5b0c6dc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fa5b0c6e6d4 RCX: 000000000045b399 RDX: 0000000000000000 RSI: 0000000020000640 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3e) already exists on: batadv_slave_1 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000942 R14: 00000000004caa57 R15: 000000000075bf2c Modules linked in: ---[ end trace 72987c71e1bcd0bd ]--- batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! RIP: 0010:nft_rhash_insert+0x87/0xe60 net/netfilter/nft_set_hash.c:166 IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready Code: 4c 89 b5 60 ff ff ff c7 01 f1 f1 f1 f1 c7 41 04 00 00 00 f2 65 48 8b 0c 25 28 00 00 00 48 89 4d d0 31 c9 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f 85 96 0b 00 00 48 8b 42 40 49 8d bd c4 18 00 00 49 batman_adv: batadv0: Interface activated: batadv_slave_1 RSP: 0018:ffff8880a3727038 EFLAGS: 00010203 RAX: dffffc0000000000 RBX: ffff8880a3727168 RCX: 03fffffffe248e02 RDX: 1ffffffff1246fd6 RSI: ffff8880a3727168 RDI: 1ffffffff1247016 IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready RBP: ffff8880a3727120 R08: dffffc0000000000 R09: 0000000000000001 IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready R10: ffffed10146e4e3e R11: ffff8880a37271f7 R12: ffff8880a37270f8 R13: ffff8880a37271c8 R14: 1ffff110146e4e13 R15: ffff8880a3727228 FS: 00007fa5b0c6e700(0000) GS:ffff8880aeb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffc231ebb00 CR3: 00000000a475f000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400