On 12/13/2016 12:38 PM, Dmitry Vyukov wrote: > On Tue, Dec 13, 2016 at 10:20 AM, Andrey Ryabinin > <aryabinin@xxxxxxxxxxxxx> wrote: >> >> >> On 12/13/2016 11:58 AM, Dmitry Vyukov wrote: >> >>> --- a/Documentation/dev-tools/kasan.rst >>> +++ b/Documentation/dev-tools/kasan.rst >>> @@ -40,6 +40,14 @@ similar to the following to the respective kernel Makefile: >>> >>> KASAN_SANITIZE := n >>> >>> +Sometimes it may be useful to disable instrumentation of reads, or writes >>> +or both for the entire kernel. For example, if binary size is a concern, >>> +it may be useful to disable instrumentation of reads to reduce binary size but >>> +still catch more harmful bugs on writes. Or, if one is interested only in >>> +sanitization of a particular module and performance is a concern, she can >>> +disable instrumentation of both reads and writes for kernel code. >>> +Instrumentation can be disabled with CONFIG_KASAN_READS and >>> CONFIG_KASAN_WRITES. >>> + >> >> I don't understand this. How this can be related to modules? Configs are global. >> You can't just disable/enable config per module. > > > Build everything without instrumentation. Then enable instrumentation > and do "make lib/test_kasan.ko". > Or build everything, copy out bzImage, change config, build everything again. Yeah, this is soooooo convenient... Seriously speaking, per-file instrumentation is absolutely irrelevant to this patch and should have been addressed from a different angle. E.g. see how UBSAN/GCOV/KCOV do that. As for this patch, I'd say only one option would be enough - KASAN_DONT_SANITIZE_READS. Nobody wants to sanitize only reads without writes, right? Writes are fewer and more dangerous. -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
