Recently I discovered the "relink" binary that sits in the bin folder of the grid infrastructure home (RAC) and the Oracle home (database). I learned that the Oracle binaries in a GI for Linux image are not compiled. When you install that image, the Oracle Universall Installer links those binaries with the OS's appropriate libraries to compile the binaries. So when those OS librairies are updated/modified, it can lead to issues with the Oracle binaries. Hence the Oracle relink tool, which relinks the Oracle binaries to the (possibly new) OS libraries.
See this pages in the Oracle documentation for reference: