==================================================================
BUG: KMSAN: uninit-value in __x64_sys_futex+0x1b9/0x200 kernel/futex.c:3557
CPU: 0 PID: 15778 Comm: syz-executor3 Not tainted 4.19.0-rc1+ #36
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+0x14b/0x190 lib/dump_stack.c:113
 kmsan_report+0x183/0x2b0 mm/kmsan/kmsan.c:956
 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:645
 __x64_sys_futex+0x1b9/0x200 kernel/futex.c:3557
 do_syscall_64+0x15b/0x220 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457089
Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9c9c249cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00000000009300a8 RCX: 0000000000457089
RDX: 0000000000000003 RSI: 0000000000000001 RDI: 00000000009300ac
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000009300ac
R13: 0000000000a3fb9f R14: 00007f9c9c24a9c0 R15: 0000000000000000

Local variable description: ----msg_sys@__sys_sendmmsg
Variable was created at:
 __sys_sendmmsg+0x98/0x930 net/socket.c:2170
 __do_sys_sendmmsg net/socket.c:2238 [inline]
 __se_sys_sendmmsg net/socket.c:2235 [inline]
 __x64_sys_sendmmsg+0x11c/0x170 net/socket.c:2235
==================================================================