On Fri, Jun 16, 2017 at 01:03:00AM +0100, Ramsay Jones wrote: > I decided to fetch this tonight and do a bit of light testing. Thanks for that. ... > I then ran sparse over the entire git project, as I usually do, to see if > there were any new errors/warnings. Unfortunately, there were, which can > be seen as follows: > > $ make builtin/rev-parse.sp > SP builtin/rev-parse.c > ./git-compat-util.h:480:22: warning: crazy programmer > ./git-compat-util.h:480:22: warning: crazy programmer > ./git-compat-util.h:480:22: warning: crazy programmer > $ > > I used git-bisect the find the commit responsible for the new warnings, > the end of that session was as follows: > > $ git bisect good > 5636cd5cbf816f30ee57d580ec4debd8e0bd7581 is the first bad commit I'm not much surprised that you see a problem with this patch but I would have hoped that these "crazy programmer" warnings would have gone away after a later commit, like it did for the kernel: (51cfbc90a "fix: kill unreachable BBs after killing a child") It visibly doesn't. > I tried to create a minimal reproducer, but I just couldn't reduce it at all! > > The warning points to the 'while' line of the skip_prefix() function in the > git-compat-util.h header file. This is used all over the place, but it seems > to be only complaining about its use in builtin/rev-parse.c. In particular, > there are 16 inlined calls in the function cmd_rev_parse() alone. So I don't > know which 3 of those inlined calls it is complaining about (the warning > message is not much help ...). Yes, the error message doesn't help much. It is emitted when a cycle is found between loads, something a correct program should never have but can happen when there is some unitilized variables that are optimized away. Here, it's obviously a bug is sparse, though. > That is as far as I have gone in trying to chase this down. I have to get > some sleep now, so I thought I should let you know what I found so far. :-D Thank you very much, it already help a lot. I'm looking at it now. -- Luc -- To unsubscribe from this list: send the line "unsubscribe linux-sparse" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
