On Thu, Feb 06, 2025 at 10:01:05AM +0100, Oscar Salvador wrote: > > That is because the above happens after __mmap_prepare(), which is > responsible of unmapping any overlapping areas, is executed. > I guess this is done this way because rolling back at this point would be > quite tricky. The big question (to me at least) is whether the current behavior is correct or not. I cannot find any documentation to that end, so maybe this is a new question we have to answer for the first time. So: In case of failure, should munmap() change the process address space? As a user I would like the answer to be "no". Partially because I was personally surprised to see a change and surprises often result in bugs. Partially because the specific change isn't even well-defined. The size of the unmapped region depends on the kernel configuration, you might unmap a 2M-aligned chunk or a 1G-aligned chunk. Are there contrary opinions out there? Would it ever be useful to have a failed mmap or munmap make changes to the process address space? Jörn -- I don't care what anything was designed to do, I care about what it can do. -- Gene Kranz
