On Sat, Feb 10, 2007 at 06:33:25PM +0100, Andi Kleen wrote: > Interesting. Did you find any kernel bugs with this? In short, not very useful yet. The current run of of sparse-0.2-cl2 on git default i386 config will find about 6 place kernel using allocated memory without NULL check. But Linus said most of them is not worthy checking because it is in the early stage of the kernel initializations. It just can't fail on those small memory allocation. May be one of them worth adding the NULL check. For interrupt and spinlock checking, it less noisier than the current sparse context level checking. The new checker code can identify inline function call, so it has more information. But it is still too noisy. I did not look at every interrupt and spinlock warning. From what I saw, it show limit of the checker itself rather than a bug in kernel. A lot of false positive is come from we don't have enough information inside a single function. e.g. sparse has not way to know some function only get called with interrupt disabled (or some lock already hold). So it assume interrupt is still enable and generate wrong warnings. Another example is that some helper function will wrap the locking function. Complain about the exit with locking hold is wrong. I am hoping adding the cross function checking will reduce those false positive. Any way, it need more information to reduce false positive. I am still working on the cross function checking. May be it will become more useful one day. Chris - 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
