On Wed, May 21, 2025 at 11:07:09AM -0600, Warner Losh wrote: > In short, I'd love to widen the interface, but there's a number of practical > issues in the way.
I think caching something in the kernel of later retrieval or adding a new return path to the ABI is the wrong way around. Instead I think the right solution is for each thread to register a userspace buffer. You end up adding one or two entries to struct thread (pointer to a structure or pointer to an buffer and length) and if the pointer is non-NULL you copyout a string to the buffer. This avoids signficant new storage in the kernel and means programs that won't use this data don't see it. It also means that the debugger can access it without needing a new PT_ argument. As a minor downside you would introduce some new error conditions if the programmer messes up registration, but we'd probably just have libthr do it in most cases (that would be more debugger friendly since you could hang it off a known location in userspace). -- Brooks
