[Bug 11800] building SES support fails w/ gcc-3.4.5

[Bug 11800] building SES support fails w/ gcc-3.4.5

[bugme-daemon]

http://bugzilla.kernel.org/show_bug.cgi?id=11800





------- Comment #1 from anonymous@kernel-bugs.osdl.org  2008-10-21 15:52 -------
Reply-To: akpm@linux-foundation.org


(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

On Tue, 21 Oct 2008 11:36:12 -0700 (PDT)
bugme-daemon@bugzilla.kernel.org wrote:

> http://bugzilla.kernel.org/show_bug.cgi?id=11800
> 
>            Summary: building SES support fails w/ gcc-3.4.5
>            Product: SCSI Drivers
>            Version: 2.5
>      KernelVersion: 2.6.27.1
>           Platform: All
>         OS/Version: Linux
>               Tree: Mainline
>             Status: NEW
>           Severity: normal
>           Priority: P1
>          Component: Other
>         AssignedTo: scsi_drivers-other@kernel-bugs.osdl.org
>         ReportedBy: bugzilla.kernel.org@beej.org
> 
> 
> [beej@dell ~]$ cat /etc/redhat-release
> CentOS release 4.3 (Final)
> [beej@dell ~]$ rpm -qf `which gcc`
> gcc-3.4.5-2
> [beej@dell linux-2.6.27.1]$ diff .config .config.old
> 4c4
> < # Tue Oct 21 14:07:00 2008
> ---
> > # Thu Oct 16 17:54:42 2008
> 1006c1006
> < # CONFIG_SCSI_ENCLOSURE is not set
> ---
> > CONFIG_SCSI_ENCLOSURE=m
> 
> using .config.old,
> [beej@dell linux-2.6.27.1]$ make
> <snip>
> Kernel: arch/x86/boot/bzImage is ready  (#2)
>   Building modules, stage 2.
>   MODPOST 668 modules
> ERROR: "__you_cannot_kmalloc_that_much" [drivers/scsi/ses.ko] undefined!
> make[1]: *** [__modpost] Error 1
> make: *** [modules] Error 2
> 

That's weird.  It means that we did a kmalloc(N, ...) where the value
of N is known at compile time, and N is too large.

But I can find no such kmalloc/kzalloc calls in ses.c.  It might be gcc
bustage - we've seen that before.

Please do

        make drivers/scsi/ses.s

then have a look in drivers/scsi/ses.s and see which function is
emitting a call to __you_cannot_kmalloc_that_much.  Or email me
drivers/scsi/ses.s and I'll take a look.

Thanks.


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[Bug 11800] building SES support fails w/ gcc-3.4.5

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http://bugzilla.kernel.org/show_bug.cgi?id=11800





------- Comment #2 from anonymous@kernel-bugs.osdl.org  2008-10-22 12:43 -------
Reply-To: beej@alum.mit.edu

At 18:52 10/21/2008, Andrew Morton wrote:
 >On Tue, 21 Oct 2008 11:36:12 -0700 (PDT)
 >bugme-daemon@bugzilla.kernel.org wrote:
 >
 >> http://bugzilla.kernel.org/show_bug.cgi?id=11800
 >>
 >>            Summary: building SES support fails w/ gcc-3.4.5
 >>            Product: SCSI Drivers
 >>            Version: 2.5
 >>      KernelVersion: 2.6.27.1
 >>           Platform: All
 >>         OS/Version: Linux
 >>               Tree: Mainline
 >>             Status: NEW
 >>           Severity: normal
 >>           Priority: P1
 >>          Component: Other
 >>         AssignedTo: scsi_drivers-other@kernel-bugs.osdl.org
 >>         ReportedBy: bugzilla.kernel.org@beej.org
 >>
 >>
 >> [beej@dell ~]$ cat /etc/redhat-release
 >> CentOS release 4.3 (Final)
 >> [beej@dell ~]$ rpm -qf `which gcc`
 >> gcc-3.4.5-2
 >> [beej@dell linux-2.6.27.1]$ diff .config .config.old
 >> 4c4
 >> < # Tue Oct 21 14:07:00 2008
 >> ---
 >> > # Thu Oct 16 17:54:42 2008
 >> 1006c1006
 >> < # CONFIG_SCSI_ENCLOSURE is not set
 >> ---
 >> > CONFIG_SCSI_ENCLOSURE=m
 >>
 >> using .config.old,
 >> [beej@dell linux-2.6.27.1]$ make
 >> <snip>
 >> Kernel: arch/x86/boot/bzImage is ready  (#2)
 >>   Building modules, stage 2.
 >>   MODPOST 668 modules
 >> ERROR: "__you_cannot_kmalloc_that_much" [drivers/scsi/ses.ko] undefined!
 >> make[1]: *** [__modpost] Error 1
 >> make: *** [modules] Error 2
 >>
 >
 >That's weird.  It means that we did a kmalloc(N, ...) where the value
 >of N is known at compile time, and N is too large.
 >
 >But I can find no such kmalloc/kzalloc calls in ses.c.  It might be gcc
 >bustage - we've seen that before.
 >
 >Please do
 >
 >      make drivers/scsi/ses.s
 >
 >then have a look in drivers/scsi/ses.s and see which function is
 >emitting a call to __you_cannot_kmalloc_that_much.  Or email me
 >drivers/scsi/ses.s and I'll take a look.

attached

marc


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[Bug 11800] building SES support fails w/ gcc-3.4.5

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http://bugzilla.kernel.org/show_bug.cgi?id=11800





------- Comment #3 from anonymous@kernel-bugs.osdl.org  2008-10-22 13:31 -------
Reply-To: akpm@linux-foundation.org

On Wed, 22 Oct 2008 15:43:05 -0400
Marc Bejarano <beej@alum.mit.edu> wrote:

> At 18:52 10/21/2008, Andrew Morton wrote:
>  >On Tue, 21 Oct 2008 11:36:12 -0700 (PDT)
>  >bugme-daemon@bugzilla.kernel.org wrote:
>  >
>  >> http://bugzilla.kernel.org/show_bug.cgi?id=11800
>  >>
>  >>            Summary: building SES support fails w/ gcc-3.4.5
>  >>            Product: SCSI Drivers
>  >>            Version: 2.5
>  >>      KernelVersion: 2.6.27.1
>  >>           Platform: All
>  >>         OS/Version: Linux
>  >>               Tree: Mainline
>  >>             Status: NEW
>  >>           Severity: normal
>  >>           Priority: P1
>  >>          Component: Other
>  >>         AssignedTo: scsi_drivers-other@kernel-bugs.osdl.org
>  >>         ReportedBy: bugzilla.kernel.org@beej.org
>  >>
>  >>
>  >> [beej@dell ~]$ cat /etc/redhat-release
>  >> CentOS release 4.3 (Final)
>  >> [beej@dell ~]$ rpm -qf `which gcc`
>  >> gcc-3.4.5-2
>  >> [beej@dell linux-2.6.27.1]$ diff .config .config.old
>  >> 4c4
>  >> < # Tue Oct 21 14:07:00 2008
>  >> ---
>  >> > # Thu Oct 16 17:54:42 2008
>  >> 1006c1006
>  >> < # CONFIG_SCSI_ENCLOSURE is not set
>  >> ---
>  >> > CONFIG_SCSI_ENCLOSURE=m
>  >>
>  >> using .config.old,
>  >> [beej@dell linux-2.6.27.1]$ make
>  >> <snip>
>  >> Kernel: arch/x86/boot/bzImage is ready  (#2)
>  >>   Building modules, stage 2.
>  >>   MODPOST 668 modules
>  >> ERROR: "__you_cannot_kmalloc_that_much" [drivers/scsi/ses.ko] undefined!
>  >> make[1]: *** [__modpost] Error 1
>  >> make: *** [modules] Error 2
>  >>
>  >
>  >That's weird.  It means that we did a kmalloc(N, ...) where the value
>  >of N is known at compile time, and N is too large.
>  >
>  >But I can find no such kmalloc/kzalloc calls in ses.c.  It might be gcc
>  >bustage - we've seen that before.
>  >
>  >Please do
>  >
>  >	make drivers/scsi/ses.s
>  >
>  >then have a look in drivers/scsi/ses.s and see which function is
>  >emitting a call to __you_cannot_kmalloc_that_much.  Or email me
>  >drivers/scsi/ses.s and I'll take a look.
> 
> attached
> 

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 :(


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[Bug 11800] building SES support fails w/ gcc-3.4.5

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http://bugzilla.kernel.org/show_bug.cgi?id=11800





------- Comment #4 from anonymous@kernel-bugs.osdl.org  2008-10-22 14:17 -------
Reply-To: James.Bottomley@HansenPartnership.com

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 :(

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.

James


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[Bug 11800] building SES support fails w/ gcc-3.4.5

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------- Comment #5 from anonymous@kernel-bugs.osdl.org  2008-10-23 09:15 -------
Reply-To: beej@alum.mit.edu

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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[Bug 11800] building SES support fails w/ gcc-3.4.5

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------- Comment #6 from anonymous@kernel-bugs.osdl.org  2008-10-23 09:35 -------
Reply-To: James.Bottomley@HansenPartnership.com

On Thu, 2008-10-23 at 12:14 -0400, Marc Bejarano wrote:
> 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:

I think we have a winner: -Os is rather less well implemented in older
versions of gcc.  Could you retry with -O2?

You do this by setting the config option

CONFIG_CC_OPTIMIZE_FOR_SIZE

to N (it defaults to Y).  If we verify this to be the root cause, we
might consider making the default for that option N if gcc version is <
4.

James


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[Bug 11800] building SES support fails w/ gcc-3.4.5

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------- Comment #7 from anonymous@kernel-bugs.osdl.org  2008-10-27 10:48 -------
Reply-To: beej@alum.mit.edu

At 12:35 10/23/2008, James Bottomley wrote:
 >On Thu, 2008-10-23 at 12:14 -0400, Marc Bejarano wrote:
 >> 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:
 >
 >I think we have a winner: -Os is rather less well implemented in older
 >versions of gcc.  Could you retry with -O2?
 >
 >You do this by setting the config option
 >
 >CONFIG_CC_OPTIMIZE_FOR_SIZE

verified.

setting CONFIG_CC_OPTIMIZE_FOR_SIZE=n in .config does allow ses.c to 
be compiled by gcc 3.4.5 from the CentOS 4 gcc-3.4.5-2 RPM.

 >If we verify this to be the root cause, we
 >might consider making the default for that option N if gcc version is <
 >4.

marc


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Alan <alan@lxorguk.ukuu.org.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |alan@lxorguk.ukuu.org.uk
         Resolution|                            |DOCUMENTED
         Regression|---                         |No




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Alan <alan@lxorguk.ukuu.org.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED




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