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Revision 448db2155fc81d2aa84f37dc58683251cba8772e authored by Thomas Wouters on 16 September 2009, 20:06:36 UTC, committed by Thomas Wouters on 16 September 2009, 20:06:36 UTC
svn+ssh://pythondev@svn.python.org/python/trunk ........ r74841 | thomas.wouters | 2009-09-16 12:55:54 -0700 (Wed, 16 Sep 2009) | 23 lines Fix issue #1590864, multiple threads and fork() can cause deadlocks, by acquiring the import lock around fork() calls. This prevents other threads from having that lock while the fork happens, and is the recommended way of dealing with such issues. There are two other locks we care about, the GIL and the Thread Local Storage lock. The GIL is obviously held when calling Python functions like os.fork(), and the TLS lock is explicitly reallocated instead, while also deleting now-orphaned TLS data. This only fixes calls to os.fork(), not extension modules or embedding programs calling C's fork() directly. Solving that requires a new set of API functions, and possibly a rewrite of the Python/thread_*.c mess. Add a warning explaining the problem to the documentation in the mean time. This also changes behaviour a little on AIX. Before, AIX (but only AIX) was getting the import lock reallocated, seemingly to avoid this very same problem. This is not the right approach, because the import lock is a re-entrant one, and reallocating would do the wrong thing when forking while holding the import lock. Will backport to 2.6, minus the tiny AIX behaviour change. ........
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Tip revision: 448db2155fc81d2aa84f37dc58683251cba8772e authored by Thomas Wouters on 16 September 2009, 20:06:36 UTC
Merged revisions 74841 via svnmerge from
Merged revisions 74841 via svnmerge from
Tip revision: 448db21
grammar.mak
# This manages to rebuild graminit.{h, c} under MSVC 6 (Windows), via
#
# nmake /f grammar.mak
#
# You may also need to copy python23.dll into this directory, or get
# it on your search path.
#
# The intermediate files can be nuked afterwards:
#
# nmake /f grammar.mak clean
#
# I don't understand the maze of preprocessor #define's on Windows, and
# as a result this requires linking with python23.lib, so it's of no use
# for bootstrapping (the cause appears to be a useless-- in this
# particular case --pragma in PC\pyconfig.h, which demands that
# python23.lib get linked in).
LIBS= ..\PCbuild\python25.lib
CFLAGS= /I ..\Include /I ..\PC /D MS_NO_COREDLL /D PGEN /MD
GRAMMAR_H= ..\Include\graminit.h
GRAMMAR_C= ..\Python\graminit.c
GRAMMAR_INPUT= ..\Grammar\Grammar
PGEN= pgen.exe
POBJS= acceler.obj grammar1.obj listnode.obj node.obj parser.obj \
parsetok.obj tokenizer.obj bitset.obj metagrammar.obj
PARSER_OBJS= $(POBJS) myreadline.obj
PGOBJS= firstsets.obj grammar.obj pgen.obj printgrammar.obj pgenmain.obj
PGENOBJS= $(POBJS) $(PGOBJS)
$(GRAMMAR_H) $(GRAMMAR_C): $(PGEN) $(GRAMMAR_INPUT)
$(PGEN) $(GRAMMAR_INPUT) $(GRAMMAR_H) $(GRAMMAR_C)
$(PGEN): $(PGENOBJS)
$(CC) $(PGENOBJS) $(LIBS) /Fe$(PGEN)
clean:
del *.obj
del $(PGEN)
Computing file changes ...