On Mon, Sep 02, 2024 at 02:07:36PM +0200, Florian Weimer wrote: > * Rich Felker: > > > This is ambiguously worded (does "operating system" mean kernel?) and > > does not agree with POSIX, which defines it as: > > > > Minimum stack size for a signal handler. > > > > And otherwise just specifies that sigaltstack shall fail if given a > > smaller size. > > > > The POSIX definition is also underspecified but it's clear that it > > should be possible to execute at least a do-nothing signal handler > > (like one which immediately returns and whose sole purpose is to > > induce EINTR when intalled without SA_RESTART), or even a minimal one > > that does something like storing to a global variable, with such a > > small stack. Allowing a size where even a do-nothing signal handler > > results in a memory-clobbering overflow or access fault seems > > non-conforming to me. > > POSIX does not specify what happens on a stack overflow (or more > generally, if most resource limits are exceeded), so I think the > behavior is conforming on a technicality. It doesn't specify what happens on overflow. It does specify what happens on non-overflow: the program executes correctly. Failure to do that is the problem here, not failure to trap on fault. Rich
