Editing Loadable kernel module (section)

== Binary compatibility ==
Linux does not provide a stable [[API]] or [[Application binary interface|ABI]] for kernel modules.  This means that there are differences in internal structure and function between different kernel versions, which can cause compatibility problems.  In an attempt to combat those problems, symbol versioning data is placed within the <code>.modinfo</code> section of loadable [[Executable and Linkable Format|ELF]] modules.  This versioning information can be compared with that of the running kernel before loading a module; if the versions are incompatible, the module will not be loaded.

Other operating systems, such as [[Solaris (operating system)|Solaris]], [[FreeBSD]], [[macOS]], and [[Microsoft Windows|Windows]] keep the kernel [[API]] and [[Application binary interface|ABI]] relatively stable, thus avoiding this problem.  For example, [[FreeBSD]] kernel modules compiled against kernel version 6.0 will work without recompilation on any other FreeBSD 6.x version, e.g. 6.4.  However, they are not compatible with other major versions and must be recompiled for use with FreeBSD 7.x, as API and ABI compatibility is maintained only within a branch.