Hi, On Fri, Dec 22, 2017 at 1:58 PM, Guenter Roeck <[email protected]> wrote: > On Thu, Dec 21, 2017 at 05:53:02PM -0800, Douglas Anderson wrote: >> Several people reported that the commit 3298b690b21c ("kbuild: Add a >> cache for generated variables") caused them problems when they updated >> gcc versions. Specifically the reports all looked something similar >> to this: >> >> > In file included from ./include/uapi/linux/uuid.h:21:0, >> > from ./include/linux/uuid.h:19, >> > from ./include/linux/mod_devicetable.h:12, >> > from scripts/mod/devicetable-offsets.c:2: >> > ./include/linux/string.h:8:20: fatal error: stdarg.h: No such file or >> > directory >> > #include <stdarg.h> >> >> Masahiro Yamada determined that the problem was with: >> >> NOSTDINC_FLAGS += -nostdinc -isystem $(call shell-cached,$(CC) >> -print-file-name=include) >> >> Specifically that the stale result of -print-file-name is stored in >> the cache file. It was determined that a "make clean" fixed the >> problems in all cases. >> >> In this particular case we could certainly try to clean just the cache >> when we detect a gcc update, but it seems like overall it's a bad idea >> to do an incremental build when gcc changes. We should warn the user >> and tell them that they need a 'make clean'. >> >> Fixes: 3298b690b21c ("kbuild: Add a cache for generated variables") >> Reported-by: Yang Shi <[email protected]> >> Reported-by: Dave Hansen <[email protected]> >> Reported-by: Mathieu Malaterre <[email protected]> >> Signed-off-by: Douglas Anderson <[email protected]> > > Unfortunately, it doesn't work as-is. Trying to build for mips with two > different compilers, and trying to run "make clean" with the 2nd compiler > version, results in: > > scripts/Kbuild.include:490: *** Detected new CC version (050400 vs 040803). > Please 'make clean'. Stop. > Makefile:1297: recipe for target '_clean_.' failed > make: *** [_clean_.] Error 2 > make: *** Waiting for unfinished jobs.... > scripts/Kbuild.include:490: *** Detected new CC version (050400 vs 040803). > Please 'make clean'. Stop. > Makefile:1297: recipe for target '_clean_arch/mips' failed > make: *** [_clean_arch/mips] Error 2 > scripts/Kbuild.include:490: *** Detected new CC version (050400 vs 040803). > Please 'make clean'. Stop. > Makefile:1297: recipe for target '_clean_arch/mips/boot/dts' failed > make: *** [_clean_arch/mips/boot/dts] Error 2 > make: *** wait: No child processes. Stop.
Indeed. I tried poking around myself today and I clearly saw this too. I believe I was just doing very simple test cases of "make help" / "make clean" yesterday and I thought that would be fine as a testcase, but clearly not. When I did a more normal make it was easy to reproduce this. Poking around it looks like MAKECMDGOALS is somehow blank sometimes as part of a "make clean". I'll post a v2 that prevents showing the error in that case too. I'll repeat the caveat that's in my cover letter that I'm a little lost when it comes to MAKECMDGOALS and how they get set in all cases, so hopefully this is the right fix. Sorry for the noise. I'm going to go ahead and post v2 today even though perhaps not everyone is done looking at v1. This is because I'll soon disappear on vacation and I'd rather have a possible fix out there. Hopefully that's OK w/ everyone. -Doug
