syzbot

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
==================================================================
BUG: KMSAN: uninit-value in netlink_rcv_skb+0x3e3/0x600 net/netlink/af_netlink.c:2437
CPU: 1 PID: 4471 Comm: syz-executor225 Not tainted 4.17.0-rc5+ #96
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+0x142/0x240 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 netlink_rcv_skb+0x3e3/0x600 net/netlink/af_netlink.c:2437
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x166b/0x1740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x1072/0x1370 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 kernel_sendmsg+0x228/0x2d0 net/socket.c:647
 sock_no_sendpage+0x1c8/0x250 net/core/sock.c:2642
 kernel_sendpage net/socket.c:3323 [inline]
 sock_sendpage+0x1de/0x2c0 net/socket.c:854
 pipe_to_sendpage+0x31b/0x430 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x49a/0xf30 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0x1c6/0x2a0 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x19b/0x200 fs/splice.c:1018
 splice_direct_to_actor+0x764/0x1040 fs/splice.c:973
 do_splice_direct+0x335/0x540 fs/splice.c:1061
 do_sendfile+0x1067/0x1e40 fs/read_write.c:1440
 __do_sys_sendfile64 fs/read_write.c:1495 [inline]
 __se_sys_sendfile64 fs/read_write.c:1487 [inline]
 __x64_sys_sendfile64+0x218/0x390 fs/read_write.c:1487
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4455f9
RSP: 002b:00007f53de890d18 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 00000000004455f9
RDX: 00000000200000c0 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 0000000000000000 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 0000000080000002 R11: 0000000000000246 R12: 00000000006dac20
R13: 00007f53de890d20 R14: 0000000000000000 R15: 0000000000000001

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:477
 _copy_from_iter_full+0xdfc/0x1450 lib/iov_iter.c:614
 copy_from_iter_full include/linux/uio.h:124 [inline]
 memcpy_from_msg include/linux/skbuff.h:3313 [inline]
 netlink_sendmsg+0xe1c/0x1370 net/netlink/af_netlink.c:1886
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg net/socket.c:639 [inline]
 kernel_sendmsg+0x228/0x2d0 net/socket.c:647
 sock_no_sendpage+0x1c8/0x250 net/core/sock.c:2642
 kernel_sendpage net/socket.c:3323 [inline]
 sock_sendpage+0x1de/0x2c0 net/socket.c:854
 pipe_to_sendpage+0x31b/0x430 fs/splice.c:451
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x49a/0xf30 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0x1c6/0x2a0 fs/splice.c:832
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x19b/0x200 fs/splice.c:1018
 splice_direct_to_actor+0x764/0x1040 fs/splice.c:973
 do_splice_direct+0x335/0x540 fs/splice.c:1061
 do_sendfile+0x1067/0x1e40 fs/read_write.c:1440
 __do_sys_sendfile64 fs/read_write.c:1495 [inline]
 __se_sys_sendfile64 fs/read_write.c:1487 [inline]
 __x64_sys_sendfile64+0x218/0x390 fs/read_write.c:1487
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:279 [inline]
 kmsan_alloc_meta_for_pages+0x161/0x3a0 mm/kmsan/kmsan.c:815
 kmsan_alloc_page+0x82/0xe0 mm/kmsan/kmsan.c:885
 __alloc_pages_nodemask+0xf8e/0x5dd0 mm/page_alloc.c:4402
 alloc_pages_current+0x6b5/0x970 mm/mempolicy.c:2093
 alloc_pages include/linux/gfp.h:494 [inline]
 push_pipe+0x680/0xca0 lib/iov_iter.c:521
 __pipe_get_pages lib/iov_iter.c:1028 [inline]
 pipe_get_pages lib/iov_iter.c:1062 [inline]
 iov_iter_get_pages+0x1357/0x1810 lib/iov_iter.c:1073
 dio_refill_pages fs/direct-io.c:170 [inline]
 dio_get_page fs/direct-io.c:214 [inline]
 do_direct_IO fs/direct-io.c:980 [inline]
 do_blockdev_direct_IO fs/direct-io.c:1331 [inline]
 __blockdev_direct_IO+0x1a4d/0x6580 fs/direct-io.c:1417
 ext4_direct_IO_read fs/ext4/inode.c:3833 [inline]
 ext4_direct_IO+0xed8/0x27c0 fs/ext4/inode.c:3865
 generic_file_read_iter+0x3bd2/0x4440 mm/filemap.c:2341
 ext4_file_read_iter+0x30f/0x520 include/linux/fs.h:728
 call_read_iter include/linux/fs.h:1778 [inline]
 generic_file_splice_read+0x5d2/0x900 fs/splice.c:307
 do_splice_to fs/splice.c:880 [inline]
 splice_direct_to_actor+0x4c6/0x1040 fs/splice.c:952
 do_splice_direct+0x335/0x540 fs/splice.c:1061
 do_sendfile+0x1067/0x1e40 fs/read_write.c:1440
 __do_sys_sendfile64 fs/read_write.c:1495 [inline]
 __se_sys_sendfile64 fs/read_write.c:1487 [inline]
 __x64_sys_sendfile64+0x218/0x390 fs/read_write.c:1487
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
==================================================================