bisecting fixing commit since 4fccc2503536a564a4ba31a1d50439854201659f building syzkaller on 2c36e7a75f8689b3da20e1a81a2ee5391f3af6e5 testing commit 4fccc2503536a564a4ba31a1d50439854201659f compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 8a61975b9d04ca1e53a1ee8329a124696ed7f9cbe0ac0903e127942d7c7e8fae all runs: crashed: kernel panic: audit: backlog limit exceeded testing current HEAD 4938296e03bd227e5020d63d418956fe52baf97c testing commit 4938296e03bd227e5020d63d418956fe52baf97c compiler: gcc version 8.4.1 20210217 (GCC) kernel signature: 17e920880acd3a5ac64868be048efe94eaa1482994fbf4ce06b083b36d6787ea all runs: crashed: kernel panic: audit: backlog limit exceeded revisions tested: 2, total time: 28m25.563555711s (build: 21m8.469144908s, test: 6m45.706196518s) the crash still happens on HEAD commit msg: Linux 4.19.198 crash: kernel panic: audit: backlog limit exceeded audit: type=1305 audit(1627050621.597:2): audit_failure=2 old=1 auid=4294967295 ses=4294967295 subj==unconfined res=1 audit: audit_backlog=4 > audit_backlog_limit=2 device veth0_macvtap entered promiscuous mode audit: audit_backlog=4 > audit_backlog_limit=2 audit: audit_lost=1 audit_rate_limit=4294967295 audit_backlog_limit=2 Kernel panic - not syncing: audit: backlog limit exceeded CPU: 0 PID: 5870 Comm: syz-executor.4 Not tainted 4.19.198-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 audit: type=1305 audit(1627050621.617:3): audit_pid=0 old=0 auid=4294967295 ses=4294967295 subj==unconfined res=1 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 audit: audit_lost=2 audit_rate_limit=4294967295 audit_backlog_limit=2 __dev_set_promiscuity.cold.176+0x265/0x390 net/core/dev.c:7475 __dev_set_rx_mode+0x1c8/0x260 net/core/dev.c:7591 dev_uc_add+0x92/0xa0 net/core/dev_addr_lists.c:496 macvlan_open+0x470/0x7a0 drivers/net/macvlan.c:635 __dev_open+0x1a6/0x310 net/core/dev.c:1402 __dev_change_flags+0x3ee/0x590 net/core/dev.c:7678 dev_change_flags+0x7b/0x150 net/core/dev.c:7747 do_setlink+0x11e7/0x2e10 net/core/rtnetlink.c:2449 rtnl_newlink+0x97f/0x1340 net/core/rtnetlink.c:3077 rtnetlink_rcv_msg+0x34f/0x8f0 net/core/rtnetlink.c:4782 netlink_rcv_skb+0x13e/0x3d0 net/netlink/af_netlink.c:2457 rtnetlink_rcv+0x10/0x20 net/core/rtnetlink.c:4800 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x443/0x650 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x764/0xc60 net/netlink/af_netlink.c:1911 sock_sendmsg_nosec net/socket.c:651 [inline] sock_sendmsg+0xb5/0xf0 net/socket.c:661 __sys_sendto+0x1f2/0x2e0 net/socket.c:1897 __do_sys_sendto net/socket.c:1909 [inline] __se_sys_sendto net/socket.c:1905 [inline] __x64_sys_sendto+0xdc/0x1a0 net/socket.c:1905 do_syscall_64+0xd0/0x4e0 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x417126 Code: 48 c7 c0 ff ff ff ff eb b7 66 2e 0f 1f 84 00 00 00 00 00 90 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 11 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 72 c3 90 55 48 83 ec 30 44 89 4c 24 2c 4c 89 RSP: 002b:00007fff2ae2b698 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000a72200 RCX: 0000000000417126 RDX: 000000000000002c RSI: 0000000000a72250 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007fff2ae2b6a4 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000a72250 Shutting down cpus with NMI Kernel Offset: disabled Rebooting in 86400 seconds..