bisecting fixing commit since 4fccc2503536a564a4ba31a1d50439854201659f
building syzkaller on 2c36e7a75f8689b3da20e1a81a2ee5391f3af6e5
testing commit 4fccc2503536a564a4ba31a1d50439854201659f with gcc (GCC) 8.1.0
kernel signature: 60b0069c9c63125543c220a9260488c419198a3b346aa9182a1b74047f80f1e7
all runs: crashed: kernel panic: audit: backlog limit exceeded
testing current HEAD 1bab61d3e8cd96f2badf515dcb06e4e1029bc017
testing commit 1bab61d3e8cd96f2badf515dcb06e4e1029bc017 with gcc (GCC) 8.1.0
kernel signature: c48e212cbd0235a81ee29eab786f1fabb1dd638058544a15573e85acb391f2b9
all runs: crashed: kernel panic: audit: backlog limit exceeded
revisions tested: 2, total time: 24m58.063085066s (build: 18m4.045180271s, test: 6m17.380795891s)
the crash still happens on HEAD
commit msg: Linux 4.19.124
crash: kernel panic: audit: backlog limit exceeded
batman_adv: It is strongly recommended to keep mac addresses unique to avoid problems!
audit: type=1305 audit(1590187148.113:17): audit_failure=2 old=2 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 res=1
audit: audit_lost=1 audit_rate_limit=4294967295 audit_backlog_limit=2
IPv6: ADDRCONF(NETDEV_UP): batadv_slave_1: link is not ready
Kernel panic - not syncing: audit: backlog limit exceeded

batman_adv: batadv0: Interface activated: batadv_slave_1
CPU: 0 PID: 6582 Comm: syz-executor.4 Not tainted 4.19.124-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
 panic+0x1cd/0x375 kernel/panic.c:186
 audit_panic.cold.22+0x28/0x28 kernel/audit.c:320
 audit_log_lost+0x57/0x120 kernel/audit.c:390
 audit_log_start+0x2e7/0x680 kernel/audit.c:1792
audit: type=1305 audit(1590187148.113:18): audit_pid=0 old=0 auid=0 ses=8 subj=system_u:system_r:kernel_t:s0 res=1
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
 audit_log+0x73/0xf0 kernel/audit.c:2383
 xt_replace_table+0x555/0x750 net/netfilter/x_tables.c:1418
 __do_replace+0x1a9/0x9b0 net/ipv6/netfilter/ip6_tables.c:1087
IPv6: ADDRCONF(NETDEV_CHANGE): batadv_slave_1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_batadv: link becomes ready
 do_replace net/ipv6/netfilter/ip6_tables.c:1160 [inline]
 do_ip6t_set_ctl+0x27e/0x3eb net/ipv6/netfilter/ip6_tables.c:1684
 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:943
 tcp_setsockopt+0x6a/0xd0 net/ipv4/tcp.c:3095
 sock_common_setsockopt+0x73/0xf0 net/core/sock.c:3049
 __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: 0033:0x45ef5a
Code: 49 89 ca b8 37 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 6a 8b fb ff c3 66 0f 1f 84 00 00 00 00 00 49 89 ca b8 36 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 4a 8b fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffebb0a06e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007ffebb0a0710 RCX: 000000000045ef5a
RDX: 0000000000000040 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 000000000071dcc0 R08: 00000000000003b8 R09: 0000000000004000
R10: 000000000071bb60 R11: 0000000000000206 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000029 R15: 000000000071bb00
Kernel Offset: disabled
Rebooting in 86400 seconds..