As pointed out in #10244 (closed) and D894, the fix we committed for this problem isn't 100% correct - from 753b156d:

#elif arm_HOST_ARCH && defined(arm_HOST_ARCH_PRE_ARMv7)
    // TODO FIXME: This case probably isn't totally correct - just because we
    // use a pre-ARMv7 toolchain (e.g. to target an old Android device), doesn't
    // mean the binary won't run on a newer ARMv7 system - in which case it
    // needs a proper barrier. So we should rethink this
    //  - Reid
    __asm__ __volatile__ ("" : : : "memory");

This is a reminder to fix this.