==================================================================
BUG: KMSAN: uninit-value in ffs arch/x86/include/asm/bitops.h:432 [inline]
BUG: KMSAN: uninit-value in netlink_sendmsg+0xb26/0x1310 net/netlink/af_netlink.c:1851
CPU: 1 PID: 11501 Comm: syz-executor7 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 ffs arch/x86/include/asm/bitops.h:432 [inline]
 netlink_sendmsg+0xb26/0x1310 net/netlink/af_netlink.c:1851
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455979
RSP: 002b:00007f466b1e3c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f466b1e46d4 RCX: 0000000000455979
RDX: 0000000000000800 RSI: 00000000205a5000 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
netlink: 'syz-executor6': attribute type 21 has an invalid length.
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000053d R14: 00000000006fbe58 R15: 0000000000000000

Local variable description: ----address@___sys_sendmsg
Variable was created at:
 ___sys_sendmsg+0xd3/0x1310 net/socket.c:1974
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
==================================================================