On Wed, Oct 18, 2023 at 09:23:49AM +0900, Masato Asou wrote: > Hello tech@ and otto, > > Why do only some calling functions store the pinttes in region_info as > below: > > static void * > malloc_bytes(struct dir_info *d, size_t size, void *f) > { > </snip> > found: > if (i == 0 && k == 0 && DO_STATS) { > struct region_info *r = find(d, bp->page); > STATS_SETF(r, f); > } > > I found following mail from otto: > https://marc.info/?l=openbsd-tech&m=168171382927798&w=2 > > The null "f" values (call sites) are due to the sampling nature of > > small allocations. Recording all call sites of all potential leaks > > introduces too much overhead. > > Is this the answer to my question? > -- > ASOU Masato
Yes. The reason is that (in the existing code) there's only one pointer per region_info available to store callers. So for a chunk page (which has many small alocations) ony slot 0 gets recorded. But there's a diff I posted last week on tech@ that will change this so that all call sites are recorded (in a different location and only if D is used). It will also report more details when a write of a free chunk is detected. That diff could use some review/testing. -Otto