On Wed, Oct 04, 2017 at 08:30:05PM +0100, Thomas Gummerer wrote: > > So I dunno. This approach is a _lot_ more convenient than trying to > > rebuild all the dependencies from scratch, and it runs way faster than > > valgrind. It did find the cases that led to the patches in this > > series, and at least one more: if the lstat() at the end of > > entry.c:write_entry() fails, we write nonsense into the cache_entry. > > Yeah valgrind found that one too, as I tried (and apparently failed :)) > to explain in the cover letter. I just haven't found the time yet to > actually try and go fix that one.
No, I just have poor memory. :) The obvious fix is that we should check the return value of `lstat`, but the bigger question is why and when that would fail. The case triggered by t0021 is using the new "delayed" filter mechanism. So at the time that write_entry() finishes, we don't actually have the file in the filesystem. I think we need to recognize that we got delayed and didn't actually check anything out, and skip that whole "if (state->refresh_cache)" block. It's not clear to me, though, how we tell the difference between the delayed and normal cases in that function. But I think this lstat could also fail if we are checking out and somebody else racily deletes our file. This is presumably sufficiently rare that I actually wonder if we should just bail with an error, so that the user knows something funny is going on. +cc Lars for thoughts no the delayed-filter case. -Peff
