At 17:17 10/22/2008, James Bottomley wrote:
>On Wed, 2008-10-22 at 13:30 -0700, Andrew Morton wrote:
>> OK, it's here:
>>
>> buf = kmalloc(vpd_len, GFP_KERNEL);
>>
>> it's a gcc bug.
>>
>> Please see if you can find some way to make it go away - perhaps change
>> vpd_len's type to `int', things like that.
>>
>> Or use a different compiler version :(
i'm not worried about compiling this. i already did a compilation
without it and i'll be fine without SES. i just selected it on the
off chance i'd find time to play with it. i was just doing my duty
of reporting this to save others the trouble.
>Could it be an optimisation issue? The static oversize test relies on
>the compiler optimising away a leg that can never be reached if the size
>is under the max. If you do a make V=1 you'll see what optimisation
>flags the compiler is using ... if it's -O2 then yes, the compiler
>should be optimising stuff away and it's a clear compiler problem. If
>it's anything else, we might have a mis setting of the optimisation
>level in the kernel build.
looks to me like -Os:
---
beej@dell linux-2.6.27.1]$ make V=1 drivers/scsi/ses.s
rm -f include/config/kernel.release
echo 2.6.27.1 > include/config/kernel.release
set -e; :; mkdir -p include/linux/; (echo \#define
LINUX_VERSION_CODE 132635; echo '#define KERNEL_VERSION(a,b,c) (((a)
<< 16) + ((b) << 8) + (c))';) <
/usr/local/src/kernel/linux-2.6.27.1/Makefile >
include/linux/version.h.tmp; if [ -r include/linux/version.h ] && cmp
-s include/linux/version.h include/linux/version.h.tmp; then rm -f
include/linux/version.h.tmp; else :; mv -f
include/linux/version.h.tmp include/linux/version.h; fi
set -e; :; mkdir -p include/linux/; if [ `echo -n "2.6.27.1" | wc -c
` -gt 64 ]; then echo '"2.6.27.1" exceeds 64 characters' >&2; exit 1;
fi; (echo \#define UTS_RELEASE \"2.6.27.1\";) <
include/config/kernel.release > include/linux/utsrelease.h.tmp; if [
-r include/linux/utsrelease.h ] && cmp -s include/linux/utsrelease.h
include/linux/utsrelease.h.tmp; then rm -f
include/linux/utsrelease.h.tmp; else :; mv -f
include/linux/utsrelease.h.tmp include/linux/utsrelease.h; fi
set -e; if [ -L include/asm ]; then asmlink=`readlink include/asm |
cut -d '-' -f 2`; if [ "$asmlink" != "x86" ]; then echo "ERROR: the
symlink include/asm points to asm-$asmlink but asm-x86 was expected";
echo " set ARCH or save .config and run 'make mrproper' to fix
it"; exit 1; fi; fi
if [ ! -L include/asm ]; then echo ' SYMLINK include/asm ->
include/asm-x86'; if [ ! -d include/asm-x86 ]; then mkdir -p
include/asm-x86; fi; ln -fsn asm-x86 include/asm; fi
mkdir -p .tmp_versions
make -f scripts/Makefile.build obj=scripts/basic
make -f scripts/Makefile.build obj=.
mkdir -p kernel/
mkdir -p arch/x86/kernel/
make -f scripts/Makefile.build obj=. missing-syscalls
/bin/sh scripts/checksyscalls.sh gcc
-Wp,-MD,./.missing-syscalls.d -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/3.4.5/include -D__KERNEL__
-Iinclude -I/usr/local/src/kernel/linux-2.6.27.1/arch/x86/include
-include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes
-Wno-trigraphs -fno-strict-aliasing -fno-common
-Werror-implicit-function-declaration -Os -m64 -mno-red-zone
-mcmodel=kernel -funit-at-a-time -maccumulate-outgoing-args
-DCONFIG_AS_CFI=1 -pipe -Wno-sign-compare
-fno-asynchronous-unwind-tables -mno-sse -mno-mmx -mno-sse2
-mno-3dnow -Iinclude/asm-x86/mach-default -fomit-frame-pointer -g
-Wdeclaration-after-statement -D"KBUILD_STR(s)=#s"
-D"KBUILD_BASENAME=KBUILD_STR(missing_syscalls)"
-D"KBUILD_MODNAME=KBUILD_STR(missing_syscalls)"
make -f scripts/Makefile.build obj=scripts
make -f scripts/Makefile.build obj=scripts/genksyms
make -f scripts/Makefile.build obj=scripts/mod
make -f scripts/Makefile.build obj=drivers/scsi drivers/scsi/ses.s
gcc -Wp,-MD,drivers/scsi/.ses.s.d -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/3.4.5/include -D__KERNEL__
-Iinclude -I/usr/local/src/kernel/linux-2.6.27.1/arch/x86/include
-include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes
-Wno-trigraphs -fno-strict-aliasing -fno-common
-Werror-implicit-function-declaration -Os -m64 -mno-red-zone
-mcmodel=kernel -funit-at-a-time -maccumulate-outgoing-args
-DCONFIG_AS_CFI=1 -pipe -Wno-sign-compare
-fno-asynchronous-unwind-tables -mno-sse -mno-mmx -mno-sse2
-mno-3dnow -Iinclude/asm-x86/mach-default -fomit-frame-pointer -g
-Wdeclaration-after-statement -D"KBUILD_STR(s)=#s"
-D"KBUILD_BASENAME=KBUILD_STR(ses)"
-D"KBUILD_MODNAME=KBUILD_STR(ses)" -fverbose-asm -S -o
drivers/scsi/ses.s drivers/scsi/ses.c
---
i'm happy to run any other easy-to-do tests in case you don't have
access to a CentOS 4 box, but it should be easy to repro for anybody
else that does.
cheers,
marc
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