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BUG: KMSAN: kernel-infoleak in _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
CPU: 0 PID: 12031 Comm: syz-executor3 Not tainted 4.20.0-rc7+ #5
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+0x173/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x12e/0x2a0 mm/kmsan/kmsan.c:613
 kmsan_internal_check_memory+0x9d4/0xb00 mm/kmsan/kmsan.c:704
 kmsan_copy_to_user+0xab/0xc0 mm/kmsan/kmsan_hooks.c:601
 _copy_to_user+0x16b/0x1f0 lib/usercopy.c:32
 copy_to_user include/linux/uaccess.h:177 [inline]
 move_addr_to_user+0x2e9/0x4f0 net/socket.c:227
netlink: 'syz-executor5': attribute type 2 has an invalid length.
 ___sys_recvmsg+0x5d7/0x1140 net/socket.c:2284
 __sys_recvmmsg+0x63d/0x1050 net/socket.c:2390
 do_sys_recvmmsg net/socket.c:2465 [inline]
 __do_sys_recvmmsg net/socket.c:2482 [inline]
 __se_sys_recvmmsg+0x1c7/0x350 net/socket.c:2478
 __x64_sys_recvmmsg+0x62/0x80 net/socket.c:2478
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457ec9
Code: 6d b7 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
netlink: 'syz-executor5': attribute type 2 has an invalid length.
RSP: 002b:00007fdbf5b90c78 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457ec9
RDX: 0000000000000300 RSI: 0000000020002ec0 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fdbf5b916d4
R13: 00000000004c4a57 R14: 00000000004d8128 R15: 00000000ffffffff

Local variable description: ----addr@___sys_recvmsg
Variable was created at:
 ___sys_recvmsg+0xf6/0x1140 net/socket.c:2245
 __sys_recvmmsg+0x63d/0x1050 net/socket.c:2390

Bytes 0-31 of 32 are uninitialized
Memory access of size 32 starts at ffff888034f1fbb0
Data copied to user address 0000000020000100
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