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BUG: KMSAN: uninit-value in copy_to_user include/linux/uaccess.h:184 [inline]
BUG: KMSAN: uninit-value in move_addr_to_user+0x32e/0x530 net/socket.c:226
CPU: 0 PID: 6655 Comm: syz-executor4 Not tainted 4.17.0-rc3+ #88
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+0x142/0x240 mm/kmsan/kmsan.c:1067
 kmsan_internal_check_memory+0x135/0x1e0 mm/kmsan/kmsan.c:1157
 kmsan_copy_to_user+0x69/0x160 mm/kmsan/kmsan.c:1199
 copy_to_user include/linux/uaccess.h:184 [inline]
 move_addr_to_user+0x32e/0x530 net/socket.c:226
 __sys_recvfrom+0x71c/0x810 net/socket.c:1849
 __do_sys_recvfrom net/socket.c:1864 [inline]
 __se_sys_recvfrom net/socket.c:1860 [inline]
 __x64_sys_recvfrom+0x1a2/0x210 net/socket.c:1860
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455979
RSP: 002b:00007f91bfc81c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
RAX: ffffffffffffffda RBX: 00007f91bfc826d4 RCX: 0000000000455979
RDX: 00000000000000fa RSI: 0000000020000040 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000020000180 R09: 00000000006f3000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000547 R14: 00000000006fbf48 R15: 0000000000000000

Local variable description: ----address@__sys_recvfrom
Variable was created at:
 __sys_recvfrom+0xec/0x810 net/socket.c:1821
 __do_sys_recvfrom net/socket.c:1864 [inline]
 __se_sys_recvfrom net/socket.c:1860 [inline]
 __x64_sys_recvfrom+0x1a2/0x210 net/socket.c:1860

Byte 19 of 32 is uninitialized
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