==================================================================
BUG: KMSAN: uninit-value in __x64_sys_futex+0x1b9/0x200 kernel/futex.c:3555
CPU: 0 PID: 6629 Comm: syz-executor4 Not tainted 4.17.0-rc5+ #103
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+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x149/0x260 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6e/0xc0 mm/kmsan/kmsan_instr.c:686
 __x64_sys_futex+0x1b9/0x200 kernel/futex.c:3555
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455a09
RSP: 002b:00007f2fcd1cec88 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f2fcd1cf6d4 RCX: 0000000000455a09
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000072becc
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000005a6 R14: 00000000006fd830 R15: 0000000000000000

Local variable description: ----msg_sys@__sys_sendmmsg
Variable was created at:
 __sys_sendmmsg+0x9c/0x850 net/socket.c:2173
 __do_sys_sendmmsg net/socket.c:2241 [inline]
 __se_sys_sendmmsg net/socket.c:2238 [inline]
 __x64_sys_sendmmsg+0x11c/0x170 net/socket.c:2238
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 6629 Comm: syz-executor4 Tainted: G    B             4.17.0-rc5+ #103
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+0x185/0x1d0 lib/dump_stack.c:113
 panic+0x39d/0x940 kernel/panic.c:184
 kmsan_report+0x260/0x260 mm/kmsan/kmsan.c:1103
 __msan_warning_32+0x6e/0xc0 mm/kmsan/kmsan_instr.c:686
 __x64_sys_futex+0x1b9/0x200 kernel/futex.c:3555
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455a09
RSP: 002b:00007f2fcd1cec88 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f2fcd1cf6d4 RCX: 0000000000455a09
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 000000000072becc
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000005a6 R14: 00000000006fd830 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..