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BUG: KMSAN: uninit-value in copyout lib/iov_iter.c:140 [inline]
BUG: KMSAN: uninit-value in _copy_to_iter+0x1b14/0x2800 lib/iov_iter.c:571
CPU: 1 PID: 11556 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
 kmsan_internal_check_memory+0x135/0x1e0 mm/kmsan/kmsan.c:1177
 kmsan_copy_to_user+0x75/0x160 mm/kmsan/kmsan.c:1219
 copyout lib/iov_iter.c:140 [inline]
 _copy_to_iter+0x1b14/0x2800 lib/iov_iter.c:571
 copy_to_iter include/linux/uio.h:106 [inline]
 skb_copy_datagram_iter+0x443/0xf70 net/core/datagram.c:431
 skb_copy_datagram_msg include/linux/skbuff.h:3268 [inline]
 netlink_recvmsg+0x6f1/0x1900 net/netlink/af_netlink.c:1959
 sock_recvmsg_nosec net/socket.c:802 [inline]
 sock_recvmsg+0x1d0/0x230 net/socket.c:809
 ___sys_recvmsg+0x3fb/0x810 net/socket.c:2279
 __sys_recvmsg net/socket.c:2328 [inline]
 __do_sys_recvmsg net/socket.c:2338 [inline]
 __se_sys_recvmsg net/socket.c:2335 [inline]
 __x64_sys_recvmsg+0x325/0x460 net/socket.c:2335
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x455a09
RSP: 002b:00007f373266ec68 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 00007f373266f6d4 RCX: 0000000000455a09
RDX: 0000000000002000 RSI: 0000000020000640 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000575 R14: 00000000006fd398 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:294 [inline]
 kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:685
 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:527
 __msan_memcpy+0x109/0x160 mm/kmsan/kmsan_instr.c:478
 __nla_put lib/nlattr.c:569 [inline]
 nla_put+0x276/0x340 lib/nlattr.c:627
 copy_to_user_policy_type net/xfrm/xfrm_user.c:1678 [inline]
 dump_one_policy+0xbe1/0x1090 net/xfrm/xfrm_user.c:1708
 xfrm_policy_walk+0x454/0xd00 net/xfrm/xfrm_policy.c:1013
 xfrm_dump_policy+0x1c0/0x2a0 net/xfrm/xfrm_user.c:1749
 netlink_dump+0x9b0/0x1540 net/netlink/af_netlink.c:2226
 __netlink_dump_start+0x1127/0x1260 net/netlink/af_netlink.c:2323
 netlink_dump_start include/linux/netlink.h:214 [inline]
 xfrm_user_rcv_msg+0x896/0x9a0 net/xfrm/xfrm_user.c:2577
 netlink_rcv_skb+0x378/0x600 net/netlink/af_netlink.c:2448
 xfrm_netlink_rcv+0xb2/0xf0 net/xfrm/xfrm_user.c:2598
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x1678/0x1750 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x104f/0x1350 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2117
 __sys_sendmsg net/socket.c:2155 [inline]
 __do_sys_sendmsg net/socket.c:2164 [inline]
 __se_sys_sendmsg net/socket.c:2162 [inline]
 __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162
 do_syscall_64+0x152/0x230 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Local variable description: ----upt.i@dump_one_policy
Variable was created at:
 dump_one_policy+0x78/0x1090 net/xfrm/xfrm_user.c:1689
 xfrm_policy_walk+0x454/0xd00 net/xfrm/xfrm_policy.c:1013

Byte 226 of 233 is uninitialized
Memory access starts at ffff880196dc101f
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