I tried some more things: 1. Compiling with clang makes no difference.
2. Compiling with -fsanitize=address results a "stack overflow" message followed by a stack trace. It doesn't reveal as much as the post-mortum traceback in gdb. The address sanitizer seems to make the error deterministic. 3. Copying the debian/ packaging directory into the git tree and compiling from there makes no difference. Most of the contents of debian/patches are already upstream anyway. 4. Switching the linker to gold makes no difference. The process map (from apport-unpack) never lists memory as [stack], and always has a double [heap] listing with a window of 0x1000 in the middle. Like this: dump9/ProcMaps:b7ccf000-bfabb000 rw-p 00000000 00:00 0 [heap] dump9/ProcMaps:bfabc000-bfb14000 rw-p 00000000 00:00 0 [heap] The stack pointer is using the second of these (i.e., in this case bfabc000-bfb14000, and the segfault is when it hits the window. Typically this allows the stack a few hundred kB (352k in the example above). It looks like something is putting the process's memory together wrongly. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to libxml2 in Ubuntu. https://bugs.launchpad.net/bugs/1471029 Title: Segfault in xsltproc on i386 Status in libxml2 package in Ubuntu: New Bug description: Running the Samba autobuild tests on a 15.04 openstack image results in a segfault in this command: /usr/bin/xsltproc --nonet -o default/docs-xml/manpages/smb.conf.5 /home/ubuntu/autobuild/b22271/samba/docs-xml/xslt/man.xsl default /docs-xml/manpages/smb.conf.5.xml I reported this upstream as a bug in xsltproc, but it was found to be impossible to reproduce using upstream source on the openstack instance: https://bugzilla.gnome.org/show_bug.cgi?id=751764 Comment 8 (https://bugzilla.gnome.org/show_bug.cgi?id=751764#c8) is particularly informative. The stack trace below shows the segfault actually occurs in libxml's xpath evaluation functions. I see no difference between xpath.c in upstream 2.9.2 and Ubuntu's version. (gdb) bt 12 #0 0xb760f874 in xmlXPathCompOpEval (ctxt=0xba25d3e8, op=0xb86bc818) at ../../xpath.c:13606 #1 0xb760f82e in xmlXPathCompOpEval (ctxt=0xba25d3e8, op=0xb86bc890) at ../../xpath.c:13598 #2 0xb7610244 in xmlXPathCompOpEval (ctxt=0xba25d3e8, op=0xb86bc8b8) at ../../xpath.c:13529 #3 0xb760f9d6 in xmlXPathCompOpEval (ctxt=0xba25d3e8, op=0xb86bc8e0) at ../../xpath.c:13977 #4 0xb7612735 in xmlXPathCompOpEval (op=<optimized out>, ctxt=0xba25d3e8) at ../../xpath.c:14552 #5 xmlXPathRunEval (ctxt=0xba25d3e8, toBool=<optimized out>) at ../../xpath.c:14552 #6 0xb76171ed in xmlXPathCompiledEvalInternal (toBool=0, resObj=<synthetic pointer>, ctxt=<optimized out>, comp=<optimized out>) at ../../xpath.c:14915 #7 xmlXPathCompiledEval__internal_alias (comp=0xb866a948, ctx=0xb99bd308) at ../../xpath.c:14978 #8 0xb7787260 in xsltEvalVariable (ctxt=ctxt@entry=0xb9836560, variable=variable@entry=0xba25d3b0, castedComp=0xb86a4238) at ../../../libxslt/variables.c:903 #9 0xb778759a in xsltBuildVariable (ctxt=0xb9836560, castedComp=0xb86a4238, tree=0xb86a6978) at ../../../libxslt/variables.c:1759 #10 0xb7788bfa in xsltParseStylesheetCallerParam (ctxt=0xb86a6978, inst=0xb86a6978) at ../../../libxslt/variables.c:1975 #11 0xb779b9db in xsltCallTemplate (ctxt=0xb9836560, node=0xb85efed8, inst=0xb86a6880, castedComp=0xb86a4148) at ../../../libxslt/transform.c:4739 (More stack frames follow...) (gdb) bt -5 #3311 0xb779a7de in xsltProcessOneNode (ctxt=0xb9836560, contextNode=0xb97586a0, withParams=0x0) at ../../../libxslt/transform.c:2097 #3312 0xb779d818 in xsltApplyStylesheetInternal (style=0xba25d3e8, style@entry=0xb85ee200, doc=0xb86bc7f0, doc@entry=0xb97586a0, params=0xb77ed340 <params>, output=0xb85e13e0 "default/docs-xml/manpages/smb.conf.5", profile=0x0, userCtxt=0xb9836560) at ../../../libxslt/transform.c:6159 #3313 0xb779df8d in xsltRunStylesheetUser (style=0xb85ee200, doc=0xb97586a0, params=0xb77ed340 <params>, output=0xb85e13e0 "default/docs-xml/manpages/smb.conf.5", SAX=0x0, IObuf=0x0, profile=0x0, userCtxt=0xb9836560) at ../../../libxslt/transform.c:6449 #3314 0xb77ea12c in xsltProcess (doc=0xb97586a0, cur=0xb85ee200, filename=0xbfd59812 "default/docs-xml/manpages/smb.conf.5.xml") at ../../../xsltproc/xsltproc.c:483 #3315 0xb77e9298 in main (argc=6, argv=0xbfd58f94) at ../../../xsltproc/xsltproc.c:903 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libxml2/+bug/1471029/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
