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BUG: KMSAN: uninit-value in copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
BUG: KMSAN: uninit-value in raw_copy_from_user arch/x86/include/asm/uaccess_64.h:55 [inline]
BUG: KMSAN: uninit-value in __copy_from_user_inatomic include/linux/uaccess.h:69 [inline]
BUG: KMSAN: uninit-value in __probe_kernel_read+0x224/0x280 mm/maccess.c:33
CPU: 0 PID: 13305 Comm: syz-executor6 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
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_from_user arch/x86/include/asm/uaccess_64.h:55 [inline]
 __copy_from_user_inatomic include/linux/uaccess.h:69 [inline]
 __probe_kernel_read+0x224/0x280 mm/maccess.c:33
 is_valid_bugaddr+0xb6/0x1a0 arch/x86/kernel/traps.c:168
 report_bug+0x6f/0x880 lib/bug.c:149
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap+0x1aa/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:ffff88018894f968 EFLAGS: 00010206
RAX: ffff8801480f0000 RBX: ffff88018894fb00 RCX: 0000000000000012
RDX: 00007ffffffff000 RSI: ffff88018894fb00 RDI: 6d64612f7665642f
RBP: ffff88018894f9b0 R08: 0000000001080020 R09: ffff880187ecfa24
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000012
R13: 6d64612f7665642f R14: 0000000000000000 R15: 00000000c58000e3
 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+0x212/0x3e0 net/socket.c:2389
 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:00007f0093d5ec68 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f0093d5f6d4 RCX: 0000000000455979
RDX: 0400000000000304 RSI: 0000000020000000 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000004a2 R14: 00000000006f9fd0 R15: 0000000000000000

Local variable description: ----sockc@udpv6_sendmsg
Variable was created at:
 udpv6_sendmsg+0x13d/0x47c0 net/ipv6/udp.c:1086
 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764
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