ab5d5c9dfd
commit 7de21e679e6a789f3729e8402bc440b623a28eae upstream.
A few archs like powerpc have different errno.h values for macros
EDEADLOCK and EDEADLK. In code including both libc and linux versions of
errno.h, this can result in multiple definitions of EDEADLOCK in the
include chain. Definitions to the same value (e.g. seen with mips) do
not raise warnings, but on powerpc there are redefinitions changing the
value, which raise warnings and errors (if using "-Werror").
Guard against these redefinitions to avoid build errors like the following,
first seen cross-compiling libbpf v5.8.9 for powerpc using GCC 8.4.0 with
musl 1.1.24:
In file included from ../../arch/powerpc/include/uapi/asm/errno.h:5,
from ../../include/linux/err.h:8,
from libbpf.c:29:
../../include/uapi/asm-generic/errno.h:40: error: "EDEADLOCK" redefined [-Werror]
#define EDEADLOCK EDEADLK
In file included from toolchain-powerpc_8540_gcc-8.4.0_musl/include/errno.h:10,
from libbpf.c:26:
toolchain-powerpc_8540_gcc-8.4.0_musl/include/bits/errno.h:58: note: this is the location of the previous definition
#define EDEADLOCK 58
cc1: all warnings being treated as errors
Cc: Stable <stable@vger.kernel.org>
Reported-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200917135437.1238787-1-Tony.Ambardar@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.