Tomasz Figa wrote: > On Friday 29 of July 2011 at 12:58:32, Tomasz Figa wrote: >>[...] >> I will try to bisect the case with s3c6400 defconfig. > > I have no idea why, but I cannot reproduce the issue anymore, even after make > distclean or starting with a clean tree. A build system bug? > > I do not know much technical details about the kernel build system, but might > it be a concurrency issue (I use make -j5 for building with 5 jobs)? Usually this is caused by symbols moving slightly between kernel compiles. This is an explanation of the process I wrote a while ago in a different thread at LKML: > Now as for CONFIG_KALLSYMS_EXTRA_PASS: to build the kallsyms table, the > build process first links a kernel image with an empty kallsyms table > and use that to fetch information for all the symbols. > > It then uses that information to build the table with the right size, > and links it again. If everything goes ok, this new version as all the > symbols in the correct places and the final table can be built with the > correct addresses. > > The final linking should produce the same result as only the data on the > kallsyms table changed, but not its size. > > However, there have been bugs in the past with section alignments and > symbol reordering for symbols with the same address, etc., etc. that > make this final table not have the exact same size, and the build fails > with an inconsistent kallsyms data message. At this point, the user can > turn on the CONFIG_KALLSYMS_EXTRA_PASS and temporarily solve the problem > while the developers find the correct fix. Without this option, in this > situation the kernel would simply fail the compilation. > > All this has been stable for a while and this option hasn't been needed > recently (AFAIK), but if there is some bug in some new binutils or > something, the option might be needed again. To check inconsistencies, the Makefile compares ".tmp_System.map" and "System.map" for differences. On a normal build they should be identical, but if this fails with "Inconsistent kallsyms data" you could try comparing the two files to check which symbols are causing trouble. -- Paulo Marques - www.grupopie.com "All generalizations are false." -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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