On Thu, Jun 04, 2020 at 07:18:37AM -0700, Guenter Roeck wrote: > On Tue, May 26, 2020 at 06:11:04PM +0200, Peter Zijlstra wrote:
> > + BUILD_BUG_ON(offsetof(struct task_struct, wake_entry_type) - > > offsetof(struct task_struct, wake_entry) != > > + offsetof(struct __call_single_data, flags) - > > offsetof(struct __call_single_data, llist)); > > + > > There is no guarantee in C that > > type1 a; > type2 b; > > in two different data structures means that offsetof(b) - offsetof(a) > is the same in both data structures unless attributes such as > __attribute__((__packed__)) are used. Do tell more; the alignment requirements and size of the types remains the same, this resulting in different layout is unlikely. I found this excellent quote on Hacker News this morning: "I think the attitude of compiler writers is a good reason to fix the spec so they can't keep ratfucking developers trying to get work done." > As result, this does and will cause a variety of build errors depending > on the compiler version and compile flags. The only thing I can think of that's actually a problem is that retarded struct randomization stuff. Anyway, I'll move cleaning it up a little higher on the todo list.
