https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80148
--- Comment #3 from Dmitry Vyukov <dvyukov at google dot com> --- > Why doesn't the kernel use atomic builtins instead? There was a recent discussion here: https://groups.google.com/forum/#!topic/kasan-dev/3sNHjjb4GCI In short: --- Trivially, The C++ model doesn't feature I/O ordering [1]... + https://lwn.net/Articles/691295/ + rmb()/wmb() are not remotely similar to atomic_thread_fenc_{acquire,release}, even if you restrict ordering to coherent CPUs (i.e. the smp_* variants). Please don't do that :) + I'm also terrified of the optimisations that the compiler is theoretically allowed to make to C11 atomics given the assumptions of the language virtual machine, which are not necessarily valid in the kernel environment. We would at least need well-supported compiler options to disable these options, and also to allow data races with things like READ_ONCE.
