A bug that doesn’t exist on x86: Exploiting an ARM-only race condition
Either I'm not understanding something that I thought I understood very well, or TFA's author's don't understand something that they think they understand very well.Their code is unsafe even on x86. You cannot write a single-writer, single-reader FIFO on modern processors without the use of memory barriers.Their attempt to use "volatile" instead of memory barriers is not appropriate. It could easily cause problems on x86 platforms in just the same way that it could on ARM. "volatile" does not mean what you think it means; if you're using it for anything other than interacting with hardware registers in a device driver, you're almost certainly using it incorrectly.You must use the correct memory barriers to protect the read/write of what they call "head" and "tail". Without them, the code is just wrong, no matter what the platform.