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f7861a55b1
Yoshiki Komachi says:
====================
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 9eea984979 ("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: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.