PHP Warning: Unknown: POST Content-Length of 问题

最近想在局域网中用PHP共享管理文件，考虑到可能会上传超大文件我把php.ini配置中post_max_size设为4096M，结果上传文件没有问题，普通的表单提交后出现如下的问题：

Warning: Unknown: POST Content-Length of 53 bytes exceeds the limit of 0 bytes in Unknown on line 0 Warning: Cannot modify header information – headers already sent in Unknown on line 0

折腾了很久，后来不断的更改post_max_size的值。

php.ini配置
post_max_size = 2048M

Warning: Unknown: POST Content-Length of 53 bytes exceeds the limit of -2147483648 bytes in Unknown on line 0 Warning: Cannot modify header information – headers already sent in Unknown on line 0

php.ini配置
post_max_size = 4096M

Warning: Unknown: POST Content-Length of 53 bytes exceeds the limit of 0 bytes in Unknown on line 0 Warning: Cannot modify header information – headers already sent in Unknown on line 0

最后发现发现post_max_size最大可以是2047M，普通表单提交没有问题。