Re: gcc tickets for sparse attributes
> > IMHO the context extension doesn't work well enough in sparse to > > document and implement as is. It would be much better if it actually was > > able to differentiate between contexts, rather than treating each one > > the same. > > That would certainly be nice, but that's something actually much more > easily done in GCC than in Sparse, given the types of information GCC > already has available to implement features like alias analysis. Right. > In any case, the spec I wrote up assumes a distinction between contexts, > but allows for an initial implementation like Sparse's that ignores the > distinction. Ok cool. :) > > This would avoid the problem that locking one lock and > > unlocking another (in the kernel's __acquire/ __release mechanism) could > > still result in a warning. > > That would actually *not* produce a warning, though it should. In > general, I *think* an implementation like Sparse's that ignores the > distinction between locks should produce false negatives but not false > positives. Right, it doesn't report one now. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: gcc tickets for sparse attributes
On Fri, Jan 17, 2014 at 09:33:16AM +0100, Johannes Berg wrote: > On Thu, 2014-01-16 at 21:27 -0800, H. Peter Anvin wrote: > > > However, I would also like support for the context extensions, but I'm > > not knowledgeable enough to describe the semantics accurately. Would > > anyone be willing to file a ticket describing how the context extension > > works well enough that it could be implemented? > > IMHO the context extension doesn't work well enough in sparse to > document and implement as is. It would be much better if it actually was > able to differentiate between contexts, rather than treating each one > the same. That would certainly be nice, but that's something actually much more easily done in GCC than in Sparse, given the types of information GCC already has available to implement features like alias analysis. In any case, the spec I wrote up assumes a distinction between contexts, but allows for an initial implementation like Sparse's that ignores the distinction. > This would avoid the problem that locking one lock and > unlocking another (in the kernel's __acquire/ __release mechanism) could > still result in a warning. That would actually *not* produce a warning, though it should. In general, I *think* an implementation like Sparse's that ignores the distinction between locks should produce false negatives but not false positives. - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: gcc tickets for sparse attributes
On Thu, Jan 16, 2014 at 09:27:08PM -0800, H. Peter Anvin wrote: > I have filed gcc tickets asking for direct support in gcc for some > sparse extensions that we use heavily in the kernel: > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59850 > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59851 > > However, I would also like support for the context extensions, but I'm > not knowledgeable enough to describe the semantics accurately. Would > anyone be willing to file a ticket describing how the context extension > works well enough that it could be implemented? http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59856 Also: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59855 - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: gcc tickets for sparse attributes
On Thu, 2014-01-16 at 21:27 -0800, H. Peter Anvin wrote: > However, I would also like support for the context extensions, but I'm > not knowledgeable enough to describe the semantics accurately. Would > anyone be willing to file a ticket describing how the context extension > works well enough that it could be implemented? IMHO the context extension doesn't work well enough in sparse to document and implement as is. It would be much better if it actually was able to differentiate between contexts, rather than treating each one the same. This would avoid the problem that locking one lock and unlocking another (in the kernel's __acquire/ __release mechanism) could still result in a warning. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: gcc tickets for sparse attributes
On 01/16/2014 09:27 PM, H. Peter Anvin wrote: > Hi, > > I have filed gcc tickets asking for direct support in gcc for some > sparse extensions that we use heavily in the kernel: > > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59850 > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59851 > Add: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59852 -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
