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BUG: KMSAN: uninit-value in do_error_trap+0x39b/0x600 arch/x86/kernel/traps.c:297
CPU: 1 PID: 7674 Comm: syz-executor5 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
 do_error_trap+0x39b/0x600 arch/x86/kernel/traps.c:297
 do_invalid_op+0x46/0x50 arch/x86/kernel/traps.c:316
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:986
RIP: 0010:kmsan_copy_to_user+0x141/0x160 mm/kmsan/kmsan.c:1213
RSP: 0018:ffff880148fdf968 EFLAGS: 00010206
RAX: ffff880147a61d80 RBX: ffff880148fdfb00 RCX: 000000000000000c
RDX: 00007ffffffff000 RSI: ffff880148fdfb00 RDI: 6f745f3168746576
RBP: ffff880148fdf9b0 R08: 0000000001080020 R09: ffff880148f0fa24
R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000c
R13: 6f745f3168746576 R14: 0000000000000000 R15: 00000000e2a000d2
 copy_to_user include/linux/uaccess.h:184 [inline]
 move_addr_to_user+0x32e/0x530 net/socket.c:227
 ___sys_recvmsg+0x4e2/0x810 net/socket.c:2211
 __sys_recvmmsg+0x54e/0xdb0 net/socket.c:2313
 SYSC_recvmmsg+0x29b/0x3e0 net/socket.c:2394
 SyS_recvmmsg+0x76/0xa0 net/socket.c:2378
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455979
RSP: 002b:00007fc69a737c68 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fc69a7386d4 RCX: 0000000000455979
RDX: 0000000000000292 RSI: 00000000200000c0 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000020fd0000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004e3 R14: 00000000006fb5e8 R15: 0000000000000000

Local variable description: ----ucreds.i@netlink_recvmsg
Variable was created at:
 netlink_recvmsg+0xe8/0x1900 net/netlink/af_netlink.c:1909
 sock_recvmsg_nosec net/socket.c:803 [inline]
 sock_recvmsg+0x1d0/0x230 net/socket.c:810
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