=====================================================
BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:154 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x6ef/0x25a0 lib/iov_iter.c:668
 instrument_copy_to_user include/linux/instrumented.h:121 [inline]
 copyout lib/iov_iter.c:154 [inline]
 _copy_to_iter+0x6ef/0x25a0 lib/iov_iter.c:668
 copy_to_iter include/linux/uio.h:162 [inline]
 simple_copy_to_iter+0xf3/0x140 net/core/datagram.c:519
 __skb_datagram_iter+0x2d5/0x11b0 net/core/datagram.c:425
 skb_copy_datagram_iter+0xdc/0x270 net/core/datagram.c:533
 skb_copy_datagram_msg include/linux/skbuff.h:3696 [inline]
 packet_recvmsg+0x78d/0x20d0 net/packet/af_packet.c:3449
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 __sys_recvfrom+0x795/0xa10 net/socket.c:2097
 __do_sys_recvfrom net/socket.c:2115 [inline]
 __se_sys_recvfrom net/socket.c:2111 [inline]
 __x64_sys_recvfrom+0x19d/0x210 net/socket.c:2111
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:737 [inline]
 slab_alloc_node mm/slub.c:3247 [inline]
 __kmalloc_node_track_caller+0xe0c/0x1510 mm/slub.c:4975
 kmalloc_reserve net/core/skbuff.c:354 [inline]
 __alloc_skb+0x545/0xf90 net/core/skbuff.c:426
 alloc_skb include/linux/skbuff.h:1158 [inline]
 alloc_skb_with_frags+0x1db/0xbc0 net/core/skbuff.c:5956
 sock_alloc_send_pskb+0xdf4/0xfc0 net/core/sock.c:2586
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2603
 __ip_append_data+0x426f/0x6490 net/ipv4/ip_output.c:1101
 ip_append_data+0x343/0x4a0 net/ipv4/ip_output.c:1325
 udp_sendmsg+0x6ff/0x4260 net/ipv4/udp.c:1280
 udp_sendpage+0x1d8/0xbe0 net/ipv4/udp.c:1338
 inet_sendpage+0x1da/0x2f0 net/ipv4/af_inet.c:833
 kernel_sendpage net/socket.c:3492 [inline]
 sock_sendpage+0x531/0x630 net/socket.c:1007
 pipe_to_sendpage+0x3f1/0x510 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x5c3/0x1000 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0x1d5/0x2c0 fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 do_splice+0x24f9/0x2df0 fs/splice.c:1079
 __do_splice fs/splice.c:1144 [inline]
 __do_sys_splice fs/splice.c:1350 [inline]
 __se_sys_splice+0x935/0xb70 fs/splice.c:1332
 __x64_sys_splice+0x19d/0x200 fs/splice.c:1332
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Bytes 24-27 of 56 are uninitialized
Memory access of size 56 starts at ffff88809d9364a4
Data copied to user address 0000000020001380

CPU: 1 PID: 27101 Comm: syz-executor.4 Not tainted 5.17.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================