bisecting fixing commit since 4fccc2503536a564a4ba31a1d50439854201659f building syzkaller on 2c36e7a75f8689b3da20e1a81a2ee5391f3af6e5 testing commit 4fccc2503536a564a4ba31a1d50439854201659f with gcc (GCC) 8.4.1 20210217 kernel signature: 3843a54fe075ce283ea7dd1ce41022a478203cc5f361f8eb88b77212ad41aabb all runs: crashed: kernel panic: audit: backlog limit exceeded testing current HEAD 1e986fe9ad15b8406034c504afc5ae76f0a8e852 testing commit 1e986fe9ad15b8406034c504afc5ae76f0a8e852 with gcc (GCC) 8.4.1 20210217 kernel signature: e72a58c864885a5084987e03b562950439fae88d47a07fe2f6f892c615c42ee8 all runs: crashed: kernel panic: audit: backlog limit exceeded revisions tested: 2, total time: 28m31.605519186s (build: 20m31.883012103s, test: 7m0.555897426s) the crash still happens on HEAD commit msg: Linux 4.19.191 crash: kernel panic: audit: backlog limit exceeded batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 audit: audit_lost=1 audit_rate_limit=4294967295 audit_backlog_limit=2 batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! audit: type=1305 audit(1621860025.825:4): audit_rate_limit=4294967295 old=0 auid=4294967295 ses=4294967295 subj==unconfined res=1 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_0 Kernel panic - not syncing: audit: backlog limit exceeded batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems! CPU: 0 PID: 5883 Comm: syz-executor.0 Not tainted 4.19.191-syzkaller #0 batman_adv: The newly added mac address (aa:aa:aa:aa:aa:3d) already exists on: batadv_slave_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+0x123/0x171 lib/dump_stack.c:118 panic+0x1cd/0x375 kernel/panic.c:186 audit_panic.cold.22+0x28/0x28 kernel/audit.c:320 audit_log_lost kernel/audit.c:390 [inline] audit_log_lost+0x57/0x120 kernel/audit.c:362 audit_log_start kernel/audit.c:1800 [inline] audit_log_start+0x2e7/0x680 kernel/audit.c:1757 audit_log+0x73/0xf0 kernel/audit.c:2391 xt_replace_table+0x55b/0x750 net/netfilter/x_tables.c:1414 __do_replace+0x1a9/0x9b0 net/ipv6/netfilter/ip6_tables.c:1087 do_replace net/ipv6/netfilter/ip6_tables.c:1160 [inline] do_ip6t_set_ctl+0x27e/0x3f0 net/ipv6/netfilter/ip6_tables.c:1686 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x5c/0xb0 net/netfilter/nf_sockopt.c:115 ipv6_setsockopt+0x95/0xf0 net/ipv6/ipv6_sockglue.c:945 tcp_setsockopt net/ipv4/tcp.c:3108 [inline] tcp_setsockopt+0x6a/0xd0 net/ipv4/tcp.c:3102 sock_common_setsockopt+0x73/0xf0 net/core/sock.c:3072 __sys_setsockopt+0x13e/0x210 net/socket.c:1901 __do_sys_setsockopt net/socket.c:1912 [inline] __se_sys_setsockopt net/socket.c:1909 [inline] __x64_sys_setsockopt+0xb9/0x150 net/socket.c:1909 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4653ca Code: 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 36 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe513a6528 EFLAGS: 00000206 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000029 RCX: 00000000004653ca RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 00007ffe513a6550 R08: 00000000000003b8 R09: 0079746972756365 R10: 0000000000509d80 R11: 0000000000000206 R12: 0000000000000003 R13: 00007ffe513a654c R14: 0000000000000000 R15: 0000000000509d20 Kernel Offset: disabled Rebooting in 86400 seconds..