linux-kernel - [PATCH 3.16 366/366] perf tools: Fix python extension build for gcc 8

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sun, 11 Nov 2018 19:49:05 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Namhyung Kim" <namhyung@...nel.org>,
        "Peter Zijlstra" <peterz@...radead.org>,
        "Jiri Olsa" <jolsa@...nel.org>, "David Ahern" <dsahern@...il.com>,
        "Arnaldo Carvalho de Melo" <acme@...hat.com>,
        "Alexander Shishkin" <alexander.shishkin@...ux.intel.com>,
        "Josh Poimboeuf" <jpoimboe@...hat.com>,
        "Sergey Senozhatsky" <sergey.senozhatsky.work@...il.com>
Subject: [PATCH 3.16 366/366] perf tools: Fix python extension build for gcc 8

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Olsa <jolsa@...nel.org>

commit b7a313d84e853049062011d78cb04b6decd12f5c upstream.

The gcc 8 compiler won't compile the python extension code with the
following errors (one example):

  python.c:830:15: error: cast between incompatible  function types from              \
  ‘PyObject * (*)(struct pyrf_evsel *, PyObject *, PyObject *)’                       \
  uct _object * (*)(struct pyrf_evsel *, struct _object *, struct _object *)’} to     \
  ‘PyObject * (*)(PyObject *, PyObject *)’ {aka ‘struct _object * (*)(struct _objeuct \
  _object *)’} [-Werror=cast-function-type]
     .ml_meth  = (PyCFunction)pyrf_evsel__open,

The problem with the PyMethodDef::ml_meth callback is that its type is
determined based on the PyMethodDef::ml_flags value, which we set as
METH_VARARGS | METH_KEYWORDS.

That indicates that the callback is expecting an extra PyObject* arg, and is
actually PyCFunctionWithKeywords type, but the base PyMethodDef::ml_meth type
stays PyCFunction.

Previous gccs did not find this, gcc8 now does. Fixing this by silencing this
warning for python.c build.

Commiter notes:

Do not do that for CC=clang, as it breaks the build in some clang
versions, like the ones in fedora up to fedora27:

  fedora:25:error: unknown warning option '-Wno-cast-function-type'; did you mean '-Wno-bad-function-cast'? [-Werror,-Wunknown-warning-option]
  fedora:26:error: unknown warning option '-Wno-cast-function-type'; did you mean '-Wno-bad-function-cast'? [-Werror,-Wunknown-warning-option]
  fedora:27:error: unknown warning option '-Wno-cast-function-type'; did you mean '-Wno-bad-function-cast'? [-Werror,-Wunknown-warning-option]
  #

those have:

  clang version 3.9.1 (tags/RELEASE_391/final)

The one in rawhide accepts that:

  clang version 6.0.0 (tags/RELEASE_600/final)

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: David Ahern <dsahern@...il.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Link: http://lkml.kernel.org/r/20180319082902.4518-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 tools/perf/util/setup.py | 2 ++
 1 file changed, 2 insertions(+)

--- a/tools/perf/util/setup.py
+++ b/tools/perf/util/setup.py
@@ -21,6 +21,7 @@ class install_lib(_install_lib):
 cflags = getenv('CFLAGS', '').split()
 # switch off several checks (need to be at the end of cflags list)
 cflags += ['-fno-strict-aliasing', '-Wno-write-strings', '-Wno-unused-parameter' ]
+cflags += ['-Wno-cast-function-type' ]

 build_lib = getenv('PYTHON_EXTBUILD_LIB')
 build_tmp = getenv('PYTHON_EXTBUILD_TMP')