Hello,
On Mon, Oct 16, 2017 at 11:33:21PM -0700, Nick Desaulniers wrote:
> When compiling arch/x86/boot/compressed/eboot.c with HOSTCC=clang, the
> following warning is observed:
>
> ./include/linux/cgroup-defs.h:391:16: warning: field 'cgrp' with
> variable sized type 'struct cgroup' not at the end of a struct or class
> is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
> struct cgroup cgrp;
> ^
> Flexible array members are a C99 feature, but must be the last member of
> a struct. Structs with flexible members composed in other structs must
> also be the final members, unless using GNU C extensions.
>
> struct cgroup_root's member cgrp is a struct cgroup, struct cgroup's
> member ancestor_ids is a flexible member.
This is silly tho. We know the the root group embedded there won't
have any ancestor_ids. Also, in general, nothing prevents us from
doing something like the following.
struct outer_struct {
blah blah;
struct inner_struct_with_flexible_array_member inner;
unsigned long storage_for_flexible_array[NR_ENTRIES];
blah blah;
};
I think we should just silence the bogus warning.
Thanks.
--
tejun
