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Date: Sat, 8 Aug 2015 21:29:58 +0900 From: Masahiro Yamada <yamada.masahiro@...ionext.com> To: Russell King - ARM Linux <linux@....linux.org.uk> Cc: linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>, Michal Marek <mmarek@...e.cz>, Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] ARM: add boot image dependencies not to generate invalid images Hi Russell, I will rephrase the git-description and post v2. 2015-07-21 15:58 GMT+09:00 Masahiro Yamada <yamada.masahiro@...ionext.com>: > Hi Russel, > > No more comment? > I answered your question. > > > > > 2015-07-11 1:41 GMT+09:00 Masahiro Yamada <yamada.masahiro@...ionext.com>: >> Hi Russel, >> >> >> 2015-07-10 19:22 GMT+09:00 Russell King - ARM Linux <linux@....linux.org.uk>: >>> On Mon, Jul 06, 2015 at 09:37:04PM +0900, Masahiro Yamada wrote: >>>> [3] Then, re-build "all" and "uImage" simultaneously. >>>> You will get an invalid uImage at random. >>>> $ make -s -j8 ARCH=arm UIMAGE_LOADADDR=0x80208000 all uImage >>>> Image Name: Linux-4.2.0-rc1-00008-g1c4c715-d >>>> Created: Mon Jul 6 17:52:22 2015 >>>> Image Type: ARM Linux Kernel Image (uncompressed) >>>> Data Size: 26768 Bytes = 26.14 kB = 0.03 MB >>>> Load Address: 80208000 >>>> Entry Point: 80208000 >>> >>> At no point in the above do I see an attempt to rebuild init/main.o, >>> which there should be as you touched the corresponding .c file - >>> because you're hiding that output with -s. Please show what's going >>> on without using -s. >> >> Please see the log attached at the end of this message. >> >> >>>> "make uImage" could descend into arch/arm/boot/Makefile before >>>> "make zImage" is completed because arch/arm/Makefile describes no >>>> dependency among boot targets. >>> >>> The uImage target should depend on vmlinux, which should force the >>> rebuild of init/main.o, and relink of the top-level vmlinux file >>> before decending into arch/arm/boot/Makefile for the >>> arch/arm/boot/uImage target. >>> >>> That makefile contains the dependencies required to order things >>> correctly - the arch/arm/boot/uImage target depends on >>> arch/arm/boot/zImage, which in turn depends on >>> arch/arm/boot/compressed/vmlinux, and then arch/arm/boot/Image. >>> >>> In other words, arch/arm/boot/Makefile deals with the dependencies >>> between the targets it's responsible for building itself. >> >> No, you do not understand what is happening in here. >> >> >> The dependencies among targets such as Image, zImage, uImage, >> are fully described in arch/arm/boot/Makefile, but it is not enough. >> >> Because arch/arm/boot/Makefile is _not_ included from the top-level Makefile, >> the top-level build cannot know the dependency between zImage and uImage. >> >> arch/arm/Makefile, which is included from the top Makefile, >> only describes that zImage depends on vmlinux, >> and uImage depends on vmlinux as well. >> But, no dependency between zImage and uImage is written in arch/arm/Makefile. >> >> Consequently, we run make with the parallel option, first Kbuild >> updates vmlinux, >> and then two different threads descends into arch/arm/boot/Makefile >> almost at the same time, one for updating zImage and the other for uImage. >> >> The is a race between the two threads. >> >> While one thread is re-generating zImage and also uImage on top of that, >> the other thread tries to re-generate zImage independently. >> >> zImage is overwritten by the slower thread, and then uImage is >> re-generated based on the broken zImage. >> >> See my detailed build log below: >> >> Please note: >> "Kernel: arch/arm/boot/zImage is ready" >> is displayed twice, >> the first one is shown before the uImage log, and the second one is >> after uImage. >> >> zImage is correct, but uImage is extremely small when this problem happens. >> >> >> >> $ git describe >> v4.2-rc1-62-gc4b5fd3 >> >> >> $ touch init/main.c >> $ make -j8 ARCH=arm UIMAGE_LOADADDR=0x80208000 all uImage >> CHK include/config/kernel.release >> CHK include/generated/uapi/linux/version.h >> CHK include/generated/utsrelease.h >> make[1]: `include/generated/mach-types.h' is up to date. >> CHK include/generated/timeconst.h >> CHK include/generated/bounds.h >> CHK include/generated/asm-offsets.h >> CALL scripts/checksyscalls.sh >> CC init/main.o >> CHK include/generated/compile.h >> LD init/built-in.o >> LINK vmlinux >> LD vmlinux.o >> MODPOST vmlinux.o >> GEN .version >> CHK include/generated/compile.h >> UPD include/generated/compile.h >> CC init/version.o >> LD init/built-in.o >> KSYM .tmp_kallsyms1.o >> KSYM .tmp_kallsyms2.o >> LD vmlinux >> SORTEX vmlinux >> SYSMAP System.map >> OBJCOPY arch/arm/boot/Image >> Building modules, stage 2. >> Kernel: arch/arm/boot/Image is ready >> GZIP arch/arm/boot/compressed/piggy.gzip >> AS arch/arm/boot/compressed/piggy.gzip.o >> Kernel: arch/arm/boot/Image is ready >> GZIP arch/arm/boot/compressed/piggy.gzip >> LD arch/arm/boot/compressed/vmlinux >> OBJCOPY arch/arm/boot/zImage >> Kernel: arch/arm/boot/zImage is ready >> UIMAGE arch/arm/boot/uImage >> Image Name: Linux-4.2.0-rc1-00062-gc4b5fd3-d >> Created: Sat Jul 11 01:22:22 2015 >> Image Type: ARM Linux Kernel Image (uncompressed) >> Data Size: 26472 Bytes = 25.85 kB = 0.03 MB >> Load Address: 80208000 >> Entry Point: 80208000 >> Image arch/arm/boot/uImage is ready >> MODPOST 192 modules >> AS arch/arm/boot/compressed/piggy.gzip.o >> LD arch/arm/boot/compressed/vmlinux >> OBJCOPY arch/arm/boot/zImage >> Kernel: arch/arm/boot/zImage is ready >> $ LANG=C ls -l arch/arm/boot/ >> total 19636 >> -rwxrwxr-x 1 masahiro masahiro 13766656 Jul 11 01:22 Image >> -rw-rw-r-- 1 masahiro masahiro 3137 Jul 3 01:17 Makefile >> drwxrwxr-x 2 masahiro masahiro 4096 Jul 3 01:17 bootp >> drwxrwxr-x 2 masahiro masahiro 4096 Jul 11 01:22 compressed >> drwxrwxr-x 3 masahiro masahiro 155648 Jul 11 00:58 dts >> -rw-rw-r-- 1 masahiro masahiro 1648 Jul 3 01:17 install.sh >> -rw-rw-r-- 1 masahiro masahiro 26536 Jul 11 01:22 uImage >> -rwxrwxr-x 1 masahiro masahiro 6135048 Jul 11 01:22 zImage >> >> >> >> >> >> >> >> -- >> Best Regards >> Masahiro Yamada > > > > -- > Best Regards > Masahiro Yamada -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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