============================= WARNING: suspicious RCU usage 4.14.307-syzkaller #0 Not tainted ----------------------------- net/tipc/bearer.c:177 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by syz-executor.1/9601: #0: (cb_lock){++++}, at: [] genl_rcv+0x15/0x40 net/netlink/genetlink.c:635 #1: (genl_mutex){+.+.}, at: [] genl_lock net/netlink/genetlink.c:33 [inline] #1: (genl_mutex){+.+.}, at: [] genl_rcv_msg+0x112/0x140 net/netlink/genetlink.c:623 stack backtrace: CPU: 0 PID: 9601 Comm: syz-executor.1 Not tainted 4.14.307-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 tipc_bearer_find+0x1ff/0x2f0 net/tipc/bearer.c:177 tipc_nl_compat_link_set+0x40b/0xb90 net/tipc/netlink_compat.c:807 __tipc_nl_compat_doit net/tipc/netlink_compat.c:316 [inline] tipc_nl_compat_doit+0x192/0x5d0 net/tipc/netlink_compat.c:364 tipc_nl_compat_handle net/tipc/netlink_compat.c:1215 [inline] tipc_nl_compat_recv+0xa0b/0xae0 net/tipc/netlink_compat.c:1297 genl_family_rcv_msg+0x572/0xb20 net/netlink/genetlink.c:600 genl_rcv_msg+0xaf/0x140 net/netlink/genetlink.c:625 netlink_rcv_skb+0x125/0x390 net/netlink/af_netlink.c:2461 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x437/0x610 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x651/0xbc0 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb5/0x100 net/socket.c:656 ___sys_sendmsg+0x6c8/0x800 net/socket.c:2062 __sys_sendmsg+0xa3/0x120 net/socket.c:2096 SYSC_sendmsg net/socket.c:2107 [inline] SyS_sendmsg+0x27/0x40 net/socket.c:2103 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x5e/0xd3 RIP: 0033:0x7f520ca8c0f9 RSP: 002b:00007f520affe168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f520cbabf80 RCX: 00007f520ca8c0f9 RDX: 0000000000000000 RSI: 0000000020000700 RDI: 0000000000000003 RBP: 00007f520cae7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffcda0073ef R14: 00007f520affe300 R15: 0000000000022000 audit: type=1326 audit(1678101857.766:2): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=9935 comm="syz-executor.0" exe="/root/syz-executor.0" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7f2d5f05f0f9 code=0x0 Zero length message leads to an empty skb netlink: 20 bytes leftover after parsing attributes in process `syz-executor.5'.