Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 20 Feb 2018 11:40:07 +0100 | Subject | Re: [PATCH v6 0/4] x86, kasan: add KASAN checks to atomic operations |
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On Wed, Feb 7, 2018 at 3:17 PM, Dmitry Vyukov <dvyukov@google.com> wrote: > On Wed, Jan 31, 2018 at 5:17 PM, Will Deacon <will.deacon@arm.com> wrote: >>> > * Will Deacon <will.deacon@arm.com> wrote: >>> >> e.g. for atomic[64]_read, your asm-generic header looks like: >>> >> >>> >> #ifndef _LINUX_ATOMIC_INSTRUMENTED_H >>> >> #define _LINUX_ATOMIC_INSTRUMENTED_H >>> >> >>> >> #include <linux/build_bug.h> >>> >> #include <linux/kasan-checks.h> >>> >> >>> >> static __always_inline int __atomic_read_instrumented(const atomic_t *v) >>> >> { >>> >> kasan_check_read(v, sizeof(*v)); >>> >> return atomic_read(v); >>> >> } >>> >> >>> >> static __always_inline s64 __atomic64_read_instrumented(const atomic64_t *v) >>> >> { >>> >> kasan_check_read(v, sizeof(*v)); >>> >> return atomic64_read(v); >>> >> } >>> >> >>> >> #undef atomic_read >>> >> #undef atomic64_read >>> >> >>> >> #define atomic_read __atomic_read_instrumented >>> >> #define atomic64_read __atomic64_read_instrumented >>> >> >>> >> #endif /* _LINUX_ATOMIC_INSTRUMENTED_H */ >>> >> >>> >> and the arch code just includes that in asm/atomic.h once it's done with >>> >> its definitions. >>> >> >>> >> What do you think? Too stinky? >>> > >>> > Hm, so while this could work - I actually *like* the low level changes: they are >>> > straightforward, trivial, easy to read and they add the arch_ prefix that makes it >>> > abundantly clear that this isn't the highest level interface. >>> > >>> > The KASAN callbacks in the generic methods are also abundantly clear and very easy >>> > to read. I could literally verify the sanity of the series while still being only >>> > half awake. ;-) >>> > >>> > Also note that the arch renaming should be 'trivial', in the sense that any >>> > missing rename results in a clear build breakage. Plus any architecture making use >>> > of this new KASAN feature should probably be tested before it's enabled - and the >>> > renaming of the low level atomic APIs kind of forces that too. >>> > >>> > So while this approach creates some churn, this series is IMHO a marked >>> > improvement over the previous iterations. >>> >>> >>> I think I mildly leaning towards Ingo's point. >>> I guess people will first find the version in arch (because that's >>> where they used to be), but that version is actually not the one that >>> is called. >>> The renaming is mechanical and you get build errors if anything is >>> wrong. It's macros that caused hard to debug runtime crashes and >>> multiple revisions of this series. >> >> Sure, and it sounds like you're proposing to do the arm64 changes anyway so >> I'm not complaining! Just thought I'd float the alternative to see what >> people think. > > > Any other comments? > Ingo, will you take this to locking tree?
Any other comments? Ingo, will you take this to locking tree?
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