On Fri, 18 Nov 2011 18:53:03 +0100 Ralf Corsepius <rc040203@xxxxxxxxxx> wrote: > On 11/18/2011 05:32 PM, Paul Howarth wrote: > > On Fri, 18 Nov 2011 15:28:27 +0000 > > Andrew Haley<aph@xxxxxxxxxx> wrote: > > > >> On 11/18/2011 11:31 AM, Paul Howarth wrote: > >>> One of my packages, pptp, suffers occasional segfaults as reported > >>> in http://bugzilla.redhat.com/749455. However, whilst > >>> investigating this, it seems to be the case that simply > >>> rebuilding the package using no optimization (-O0) as opposed to > >>> the default -O2 is enough to stop this happening. > >>> > >>> This raises two questions (at least!): > >>> > >>> 1. Is it reasonable for me to flout the packaging guidelines by > >>> rebuilding with -O0 until this is resolved? > >>> > >>> 2. How to determine what the actual problem is, e.g. a problem > >>> with the way the code is written leading to unsafe optimizations, > >>> or a gcc bug? > >> > >> You're just going to have to debug it. > >> > >> To start with, build with warnings, and look at them all. If none > >> of that works and you're stuck, I'll have a look. > > > > It already builds with -Wall and there are no warnings: > This doesn't mean much. > > Adding a couple of more agressive options, this is what happens to > pptp: > > orckit_quirks.c:65:2: warning: missing initializer > [-Wmissing-field-initializers] > orckit_quirks.c:65:2: warning: (near initialization for > 'fixed_packet.header.pptp_type') [-Wmissing-field-initializers] > pptp.c:147:21: warning: unused parameter 'sig' [-Wunused-parameter] > pptp.c:153:19: warning: unused parameter 'sig' [-Wunused-parameter] > pptp.c:459:33: warning: dereferencing type-punned pointer might break > strict-aliasing rules [-Wstrict-aliasing] > pptp.c:492:65: warning: unused parameter 'argc' [-Wunused-parameter] > pptp_callmgr.c:105:48: warning: unused parameter > 'envp' [-Wunused-parameter] pptp_callmgr.c:202:48: warning: > dereferencing type-punned pointer might break strict-aliasing rules > [-Wstrict-aliasing] pptp_callmgr.c:215:17: warning: ignoring return > value of 'read', declared with attribute warn_unused_result > [-Wunused-result] pptp_callmgr.c:216:17: warning: ignoring return > value of 'read', declared with attribute warn_unused_result > [-Wunused-result] pptp_callmgr.c:325:29: warning: dereferencing > type-punned pointer might break strict-aliasing rules > [-Wstrict-aliasing] pptp_callmgr.c:330:28: warning: dereferencing > type-punned pointer might break strict-aliasing rules > [-Wstrict-aliasing] pptp_callmgr.c:358:25: warning: dereferencing > type-punned pointer might break strict-aliasing rules > [-Wstrict-aliasing] pptp_callmgr.c:368:44: warning: unused parameter > 'inetaddr' [-Wunused-parameter] > pptp_callmgr.c:39:29: warning: unused parameter > 'sig' [-Wunused-parameter] pptp_callmgr.c:44:29: warning: unused > parameter 'sig' [-Wunused-parameter] pptp_callmgr.c:71:18: warning: > ignoring return value of 'write', declared with attribute > warn_unused_result [-Wunused-result] pptp_ctrl.c:1062:13: warning: > function declaration isn't a prototype [-Wstrict-prototypes] > pptp_ctrl.c:177:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > pptp_ctrl.c:206:31: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_ctrl.c:245:13: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_ctrl.c:535:14: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:237:27: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:241:30: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:249:18: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:260:23: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:441:26: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:446:23: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:493:27: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:527:19: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > pptp_gre.c:74:10: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > pptp_gre.c:85:19: warning: nested extern declaration of 'localbind' > [-Wnested-externs] > pptp_gre.c:92:29: warning: dereferencing type-punned pointer might > break strict-aliasing rules [-Wstrict-aliasing] > pptp_gre.c:99:28: warning: dereferencing type-punned pointer might > break strict-aliasing rules [-Wstrict-aliasing] > pptp_quirks.c:33:5: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > pptp_quirks.h:56:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > pqueue.c:220:11: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > pqueue.h:27:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > routing.c:117:8: warning: ignoring return value of 'fgets', declared > with attribute warn_unused_result [-Wunused-result] > routing.c:125:6: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > routing.c:155:6: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > routing.h:2:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > routing.h:3:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > test.c:145:14: warning: comparison between signed and unsigned > integer expressions [-Wsign-compare] > test.c:174:27: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > test.c:55:16: warning: comparison between signed and unsigned integer > expressions [-Wsign-compare] > test.c:99:14: warning: comparison between signed and unsigned integer > expressions [-Wsign-compare] > test.h:5:8: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.c:121:8: warning: ignoring return value of 'write', declared > with attribute warn_unused_result [-Wunused-result] > util.c:136:5: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.c:142:5: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.c:145:7: warning: ignoring return value of 'read', declared with > attribute warn_unused_result [-Wunused-result] > util.c:149:6: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.c:90:5: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.h:38:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.h:47:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.h:50:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > util.h:52:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > vector.c:38:9: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > vector.h:15:1: warning: function declaration isn't a prototype > [-Wstrict-prototypes] > > I can't spot anything obvious, but each of these are potential > candiates for issues and should be inspected. Hmm, thanks for that. I naively assumed that -Wall was "all warnings"! I'll look into those. > >> This is unlikely to be a gcc bug. > >> > >> Does the upstream package segfault? > > > > Upstream's Makefile uses -O0 and doesn't appear to segfault > > (probably as a result). > Does upstream have an explanation why they are doing so? > > If being hostile, one would be tempted to consider this to be an > attempt to play down known issues of sloppy programming :-) Actually the comment that went with the original commit (a long time ago) was that it was to make debugging easier. Paul. -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
