Date: Mon, 17 Jun 2019 02:48:03 +0000 From: "Farhan Khan" <farhan@farhan.codes> To: "David CARLIER" <devnexen@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Valgrind memcheck showing question marks Message-ID: <c3618d93b9e3f420a84923f2ce0efe95@farhan.codes> In-Reply-To: <CA%2BXhMqxx48M4Xhx6QLfzFdaNgWPht99utHQbU-HFKPfaext%2B3A@mail.gmail.com> References: <CA%2BXhMqxx48M4Xhx6QLfzFdaNgWPht99utHQbU-HFKPfaext%2B3A@mail.gmail.com> <20190605095411.GA8120@pc.farhan.codes>
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June 5, 2019 5:58 AM, "David CARLIER" <devnexen@gmail.com> wrote: > Hi if that helps you can try -O0 in addition of -g. > > Regards. > > On Wed, 5 Jun 2019 at 09:56, Farhan Khan via freebsd-hackers > <freebsd-hackers@freebsd.org> wrote: > >> Hi all, >> >> I am having a Segmentation fault error and trying to use valgrind to help me find where the >> overflow occurs. I run valgrind on the prog.full version of the executable. >> >> I am running it as follows: >> >> $ valgrind --tool=memcheck ogit.full [arguments omitted] >> >> ==14457== Memcheck, a memory error detector >> ==14457== Copyright (C) 2002-2013, and GNU GPL'd, by Julian Seward et al. >> ==14457== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info >> ==14457== Command: ogit.full clone http://git.farhan.codes/farhan/opengit >> ==14457== >> ==14457== Conditional jump or move depends on uninitialised value(s) >> ==14457== at 0x49D1867: ??? (in /lib/libc.so.7) >> ==14457== by 0x7FF00051F: ??? >> ==14457== by 0x20DE7D: ??? (in /usr/home/farhan/opengit/ogit.full) >> ==14457== by 0x20ECE1: ??? (in /usr/home/farhan/opengit/ogit.full) >> ==14457== by 0x2054B5: ??? (in /usr/home/farhan/opengit/ogit.full) >> ==14457== by 0x20511A: ??? (in /usr/home/farhan/opengit/ogit.full) >> ==14457== by 0x4826FFF: ??? >> ==14457== >> [snippet] >> >> Please note that the stack trace does not show the function names, which I need. How do I enable >> those symbols? >> >> The Makefile is as follows: >> ------------------ >> MAN= >> >> CFLAGS= -Wall -lmd -lz -lfetch >> >> PROG= ogit >> >> SRCS= ogit.c lib/ini.c lib/index.c lib/common.c lib/pack.c remote.c init.c \ >> lib/zlib-handler.c lib/buffering.c lib/loose.c \ >> hash-object.c update-index.c cat-file.c log.c clone.c index-pack.c >> >> CLEANFILES+= ${PROG}.core >> >> .include <bsd.prog.mk> >> ------------------ >> >> An example compilation line and the ending is as follows. The first line is for "index-pack.c", but >> there are others as the SRCS line shows. >> ------------------ >> cc -Wall -lmd -lz -lfetch -g -MD -MF.depend.index-pack.o -MTindex-pack.o -std=gnu99 >> -fstack-protector-strong -Qunused-arguments -c index-pack.c -o index-pack.o >> cc -Wall -lmd -lz -lfetch -g -std=gnu99 -fstack-protector-strong -Qunused-arguments -o ogit.full >> ogit.o lib/ini.o lib/index.o lib/common.o lib/pack.o remote.o init.o lib/zlib-handler.o >> lib/buffering.o lib/loose.o hash-object.o update-index.o cat-file.o log.o clone.o index-pack.o >> objcopy --only-keep-debug ogit.full ogit.debug >> objcopy --strip-debug --add-gnu-debuglink=ogit.debug ogit.full ogit >> ------------------ >> >> Am I missing a necessary compilation flag to have those symbols appear? I have "-g" turned on >> during compilation. >> Thanks, >> >> --- >> Farhan Khan >> PGP Fingerprint: 1312 89CE 663E 1EB2 179C 1C83 C41D 2281 F8DA C0DE I have -O0 and -g in my Makefile, but that does not appear to change the issue. It appears that debugging symbols are stripped out towards the end of the compilation and creates 'prog.full' and 'prog.debug', as follows: cc -O2 -pipe -Wunreachable-code -Werror -O0 -g -Wall -I/usr/home/farhan/opengit/src/.. -g -std=gnu99 -fstack-protector-strong -Qunused-arguments -lmd -lz -lfetch /usr/home/farhan/opengit/src/../lib/libogit.a -o ogit.full ogit.o remote.o init.o hash-object.o update-index.o cat-file.o log.o clone.o clone_http.o index-pack.o objcopy --only-keep-debug ogit.full ogit.debug objcopy --strip-debug --add-gnu-debuglink=ogit.debug ogit.full ogit Notice how the debugging symbols are written to "ogit.debug". Is there a way to use that debug file with valgrind? I should add, I also tried to manually run the compilation line without the two objcopy(1) lines, but valgrind also produced the same result. Assistance is appreciated :) Thanks, --- Farhan Khan PGP Fingerprint: 1312 89CE 663E 1EB2 179C 1C83 C41D 2281 F8DA C0DEhelp
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