Re: [Crash-utility] [PATCH] Fixed the segment fault when ikconfig passed nonstandard values

Hi Jackie, Hatayama san, -----Original Message----- > 在 2021/1/4 下午1:00, d.hatayama(a)fujitsu.com 写道: >>>> Some strange reasons may cause kcore to collect some strange >>>> entries of ikconfig, such as CONFIG_SECU+[some hex data] causes >>> Could you tell me the example of such CONFIG_SEC+[some hex data] that >>> causes the val to have NULL. I tried to reproduce but failed. > > It's hard to say about that, because It's just appeared in the virtual > machine, when I debug > > with vmcore (Not a dump.xxx file in my memory). > > > Ubuntu-kernel/debian/rules.d/2-binary-arch.mk has that: > > $(stampdir)/stamp-prepare-tree-%: $(archconfdir)/kylinos_%_defconfig > debian/scripts/fix-filenames >         @echo Debug: $@ >         install -d $(builddir)/build-$* >         touch $(builddir)/build-$*/ubuntu-build >         [ "$(do_full_source)" != 'true' ] && true || \ >                 rsync -a --exclude debian --exclude debian.master > --exclude $(DEBIAN) * $(builddir)/build-$* >         cat $(wordlist 1,3,$^) | sed -e > 's/.*CONFIG_VERSION_SIGNATURE.*/CONFIG_VERSION_SIGNATURE="KYLINOS > $(release)-$(revision)-$* $(raw_kernelversion)"/' > > $(builddir)/build-$*/.config >         find $(builddir)/build-$* -name "*.ko" | xargs rm -f >         $(build_cd) $(kmake) $(build_O) -j1 olddefconfig syncconfig > prepare scripts >         touch $@ > > Every time,  '.config' has object file 'fix-filenames' hex data with > config, maybe that is an reason, but > > I'm not sure. Maybe It's just any other strange reason cause > /proc/vmcore has CONFIG_SECU+[hex data]. > >> I guess you mean CONFIG_SECU+[some hex data] to be **strings that don't >> contain the delimitor string '='** and then strtok_r() interprets >> it as consisting of a single token, hence val resulting in having NULL. >> If so, I think it's better to write so. (Thanks for the comment.) > > Yes, It is. Could you add more words like the above "entries that do not contain the delimiter string '='" to the commit message?

> >> OTOH, due to the cause of this issue, is there also possibility >> that the broken line contains two or more '=' and broken name >> and values are appended in the ikconfig list? It has to be less >> important than here because it doesn't result in segfault, but >> it might be necessary to deal with it too depending on its actual impact. Two or more '=' characters except for the first one will be added to the value. It can be an arbitrary string, so I think it would be hard to check if a value is valid or not here. If we check it, we should do when using the value. But I don't think the entries that crash uses can break easily.. Thanks, Kazu