On Fri, Oct 16, 2015 at 12:44:53PM +0300, Andrey Ryabinin wrote: > Some code may perform racy by design memory reads. This could be > harmless, yet such code may produce KASAN warnings. > > To hide such accesses from KASAN this patch introduces > READ_ONCE_NOKSAN() macro. KASAN will not check the memory > accessed by READ_ONCE_NOKSAN(). The KernelThreadSanitizer (KTSAN) > is going to ignore it as well. > > This patch creates __read_once_size_noksan() a clone of > __read_once_size(). The only difference between them is > 'no_sanitized_address' attribute appended to '*_nokasan' function. > This attribute tells the compiler that instrumentation of memory > accesses should not be applied to that function. We declare it as > static '__maybe_unsed' because GCC is not capable to inline such > function: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 > > With KASAN=n READ_ONCE_NOKSAN() is just a clone of READ_ONCE().
Would we need a similar annotation for things like mutex_spin_on_owner()'s dereference of owner, or is that considered safe by KASAN? (its not actually safe; as I remember we have a problem with using rcu_read_lock for tasks like that) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
