Re: [patch] Re: Disable -lmcheck when Python has threads (Re: [BUG] gdb crash when "python import gtk")

[Khoo Yit Phang <khooyp@cs.umd.edu>]

[-- Attachment #1: Type: text/plain, Size: 1709 bytes --]

Hi,

On Aug 30, 2012, at 2:21 PM, Jan Kratochvil wrote:

> On Thu, 30 Aug 2012 20:05:01 +0200, Khoo Yit Phang wrote:
>> 1) I reverted python-config.py and used a different method to test for
>> threads ("python -m threading");
> 
> Unfortunately it does not work for me with python-2.7, only with python-3.3,
> tested on Fedora 18 x86_64:
> 
> $ python3 -m threading;echo $?
> 0
> $ python3 -m threadin;echo $?
> /usr/bin/python3: No module named threadin
> 1
> 
> but:
> 
> $ python2 -m threading;echo $?
> Traceback (most recent call last):
>  File "/usr/lib64/python2.7/runpy.py", line 162, in _run_module_as_main
>    "__main__", fname, loader, pkg_name)
>  File "/usr/lib64/python2.7/runpy.py", line 72, in _run_code
>    exec code in run_globals
>  File "/usr/lib64/python2.7/threading.py", line 985, in <module>
>    _test()
>  File "/usr/lib64/python2.7/threading.py", line 969, in _test
>    Q = BoundedQueue(QL)
>  File "/usr/lib64/python2.7/threading.py", line 912, in __init__
>    self.queue = deque()
> NameError: global name 'deque' is not defined
> 255
> 
> python3-3.3.0-0.3.b2.fc18.x86_64
> python-2.7.3-13.fc18.x86_64
> 
> GDB moveover currently is not compatible with python3.x at all.
> 
> I do not know much Python but I would guess thread-less Pythons are rare,
> aren't they?  There would be also a possibility to assume Python is threaded,
> if one already links with Python.

That's strange, it works for me under Ubuntu 11.04 with Python 2.7.1 and RHEL5 with Python 2.6.6. I suppose it would be easier to just assume Python is threaded, this new patch does that. I'll check it in if it looks alright.

Thanks,

Yit
August 30, 2012


[-- Attachment #2: mcheck-python.txt --]
[-- Type: text/plain, Size: 2749 bytes --]

# HG changeset patch
# Parent 38ae59cbbba369e1b4bd78b4b2f378e26548b79d
Do not enable -lmcheck by default when Python is enabled.

gdb/ChangeLog:

2012-08-30  Khoo Yit Phang  <khooyp@cs.umd.edu>

	Do not enable -lmcheck by default when Python is enabled.
	* configure.ac: Move --enable-lmcheck after --with-python.
	Do not enable -lmcheck by default if have_libpython=yes.
	Warn if --enable-lmcheck=yes and have_libpython=yes.
	* configure: Regenerate.

diff --git a/gdb/configure.ac b/gdb/configure.ac
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -645,28 +645,6 @@
 AC_SUBST(READLINE_CFLAGS)
 AC_SUBST(READLINE_TEXI_INCFLAG)
 
-# Provide a --enable-libmcheck/--disable-libmcheck set of options
-# allowing a user to enable this option even when building releases,
-# or to disable it when building a snapshot.
-AC_ARG_ENABLE(libmcheck,
-  AS_HELP_STRING([--enable-libmcheck],
-                 [Try building GDB with -lmcheck if available]),
-  [case "${enableval}" in
-     yes | y) ENABLE_LIBMCHECK="yes" ;;
-     no | n)  ENABLE_LIBMCHECK="no" ;;
-     *) AC_MSG_ERROR(bad value ${enableval} for --enable-libmcheck) ;;
-   esac])
-
-# Enable -lmcheck by default (it provides cheap-enough memory mangling),
-# but turn it off for releases.
-if test -z "${ENABLE_LIBMCHECK}" && $development; then
-    ENABLE_LIBMCHECK=yes
-fi
-
-if test "$ENABLE_LIBMCHECK" = "yes" ; then
-  AC_CHECK_LIB(mcheck, main)
-fi
-
 # Generate jit-reader.h
 
 # This is typedeffed to GDB_CORE_ADDR in jit-reader.h
@@ -1028,6 +1006,32 @@
 AC_SUBST(PYTHON_CPPFLAGS)
 AC_SUBST(PYTHON_LIBS)
 
+# Provide a --enable-libmcheck/--disable-libmcheck set of options
+# allowing a user to enable this option even when building releases,
+# or to disable it when building a snapshot.
+AC_ARG_ENABLE(libmcheck,
+  AS_HELP_STRING([--enable-libmcheck],
+                 [Try building GDB with -lmcheck if available]),
+  [case "${enableval}" in
+     yes | y) ENABLE_LIBMCHECK="yes" ;;
+     no | n)  ENABLE_LIBMCHECK="no" ;;
+     *) AC_MSG_ERROR(bad value ${enableval} for --enable-libmcheck) ;;
+   esac])
+
+# Enable -lmcheck by default (it provides cheap-enough memory mangling),
+# but turn it off if Python is enabled with threads, and for releases.
+if test -z "${ENABLE_LIBMCHECK}" -a "${have_libpython}" = "no" \
+    && $development ; then
+  ENABLE_LIBMCHECK=yes
+fi
+
+if test "$ENABLE_LIBMCHECK" = "yes" ; then
+  if test "${have_libpython}" != "no" ; then
+    AC_MSG_WARN(--enable-libmcheck may lead to spurious crashes if threads are used in python)
+  fi
+  AC_CHECK_LIB(mcheck, main)
+fi
+
 # ------------------------- #
 # Checks for header files.  #
 # ------------------------- #

[-- Attachment #3: Type: text/plain, Size: 3 bytes --]