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BUG: KMSAN: kernel-infoleak in copyout lib/iov_iter.c:140 [inline]
BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x471/0x2640 lib/iov_iter.c:571
CPU: 0 PID: 11601 Comm: syz-executor1 Not tainted 4.19.0-rc7+ #69
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+0x306/0x460 lib/dump_stack.c:113
 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:917
 kmsan_internal_check_memory+0x2cd/0x460 mm/kmsan/kmsan.c:971
 kmsan_copy_to_user+0x89/0xe0 mm/kmsan/kmsan_hooks.c:552
 copyout lib/iov_iter.c:140 [inline]
 _copy_to_iter+0x471/0x2640 lib/iov_iter.c:571
 copy_to_iter include/linux/uio.h:106 [inline]
 skb_copy_datagram_iter+0x4c3/0x1040 net/core/datagram.c:431
 skb_copy_datagram_msg include/linux/skbuff.h:3279 [inline]
 packet_recvmsg+0x717/0x1c00 net/packet/af_packet.c:3327
 sock_recvmsg_nosec net/socket.c:794 [inline]
 sock_recvmsg net/socket.c:801 [inline]
 sock_read_iter+0x45a/0x4e0 net/socket.c:878
 do_iter_readv_writev+0x822/0xab0 include/linux/fs.h:1802
 do_iter_read+0x301/0xe20 fs/read_write.c:922
 vfs_readv fs/read_write.c:986 [inline]
 do_readv+0x2b9/0x620 fs/read_write.c:1019
 __do_sys_readv fs/read_write.c:1106 [inline]
 __se_sys_readv+0x9b/0xb0 fs/read_write.c:1103
 __x64_sys_readv+0x4a/0x70 fs/read_write.c:1103
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457569
Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7e2d707c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000013
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7e2d7086d4
R13: 00000000004c30a4 R14: 00000000004d4d10 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:255 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:180
 kmsan_kmalloc+0xa4/0x120 mm/kmsan/kmsan_hooks.c:104
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:113
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2727 [inline]
 __kmalloc_node_track_caller+0xb43/0x1400 mm/slub.c:4360
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x422/0xe90 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:996 [inline]
 alloc_skb_with_frags+0x1d0/0xac0 net/core/skbuff.c:5273
 sock_alloc_send_pskb+0xe00/0x1420 net/core/sock.c:2082
 packet_alloc_skb net/packet/af_packet.c:2781 [inline]
 packet_snd net/packet/af_packet.c:2872 [inline]
 packet_sendmsg+0x6874/0x9170 net/packet/af_packet.c:2953
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 __sys_sendto+0x975/0xb70 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1796
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1796
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Bytes 4-5 of 44 are uninitialized
Memory access of size 44 starts at ffff8801cda26664
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