On Tue, Mar 10, 2020 at 9:46 AM Martin KaFai Lau <kafai@xxxxxx> wrote:
>
> On Tue, Mar 10, 2020 at 04:32:28PM +0900, Yoshiki Komachi wrote:
> > btf_enum_check_member() checked if the size of "enum" as a struct
> > member exceeded struct_size or not. Then, the function compared it
> > with the size of "int". Although the size of "enum" is 4-byte by
> > default (i.e., equivalent to "int"), the packing feature enables
> > us to reduce it, as illustrated by the following example:
> >
> > struct A {
> > char m;
> > enum { E0, E1 } __attribute__((packed)) n;
> > };
> >
> > With such a setup above, the bpf loader gave an error attempting
> > to load it:
> >
> > ------------------------------------------------------------------
> > ...
> >
> > [3] ENUM (anon) size=1 vlen=2
> > E0 val=0
> > E1 val=1
> > [4] STRUCT A size=2 vlen=2
> > m type_id=2 bits_offset=0
> > n type_id=3 bits_offset=8
> >
> > [4] STRUCT A size=2 vlen=2
> > n type_id=3 bits_offset=8 Member exceeds struct_size
> >
> > libbpf: Error loading .BTF into kernel: -22.
> >
> > ------------------------------------------------------------------
> >
> > The related issue was previously fixed by the commit 9eea98497951 ("bpf:
> > fix BTF verification of enums"). On the other hand, this series fixes
> > this issue as well, and adds a selftest program for it.
> >
> > Changes in v2:
> > - change an example in commit message based on Andrii's review
> > - add a selftest program for packed "enum" type members in struct/union
> Acked-by: Martin KaFai Lau <kafai@xxxxxx>
Applied to bpf tree. Thanks
