there is also some weirdness or used to be some weirdness with linux and modifying shared libraries. for example if you have a process is using a shared library and the contents of the file is modified (same inode) then what behaviour is expected? i think there are two main problems
1) pages from the shared library are lazily loaded into memory so if you try and access a new page you are going to get it from the new binary which is likely to cause problems
2) pages from the shared library might be 'swapped' back to disk due to memory pressure. not sure whether the pager will just throw the page away and try to swap back in from disk from the new file contents or if it will notice the disk page is dirty and use the swap for write back to preserve the original page.
also, i remember it used to be possible to trigger some error if you tried to open a shared library for writing while it was in use but I can't seem to trigger that error anymore.
1) pages from the shared library are lazily loaded into memory so if you try and access a new page you are going to get it from the new binary which is likely to cause problems
2) pages from the shared library might be 'swapped' back to disk due to memory pressure. not sure whether the pager will just throw the page away and try to swap back in from disk from the new file contents or if it will notice the disk page is dirty and use the swap for write back to preserve the original page.
also, i remember it used to be possible to trigger some error if you tried to open a shared library for writing while it was in use but I can't seem to trigger that error anymore.