Re: linux-next: Tree for July 28 ("copy_from_user_overflow" undefined)

[Sedat Dilek]

On Fri, Jul 29, 2011 at 11:45 AM, Sedat Dilek
<sedat.dilek@xxxxxxxxxxxxxx> wrote:
> On Fri, Jul 29, 2011 at 11:02 AM, Sedat Dilek
> <sedat.dilek@xxxxxxxxxxxxxx> wrote:
>> On Fri, Jul 29, 2011 at 7:09 AM, Randy Dunlap <rdunlap@xxxxxxxxxxxx> wrote:
>>> On Fri, 29 Jul 2011 03:34:26 +0200 Sedat Dilek wrote:
>>>
>>>> On Fri, Jul 29, 2011 at 1:01 AM, Randy Dunlap <rdunlap@xxxxxxxxxxxx> wrote:
>>>> > On Thu, 28 Jul 2011 16:05:31 +0200 Sedat Dilek wrote:
>>>> >
>>>> >> Hi,
>>>> >>
>>>> >> just see this build-break on the last mile:
>>>> >>
>>>> >> [...]
>>>> >> Â OBJCOPY arch/x86/boot/compressed/vmlinux.bin
>>>> >> Â HOSTCC Âarch/x86/boot/compressed/relocs
>>>> >> Â HOSTCC Âarch/x86/boot/compressed/mkpiggy
>>>> >> /mnt/sdb3/linux-kernel/linux-3.0/debian/build/source_i386_none/arch/x86/boot/compressed/relocs.c:
>>>> >> In function 'print_absolute_symbols':
>>>> >> /mnt/sdb3/linux-kernel/linux-3.0/debian/build/source_i386_none/arch/x86/boot/compressed/relocs.c:405:14:
>>>> >> warning: variable 'sh_symtab' set but not used
>>>> >> [-Wunused-but-set-variable]
>>>> >> ERROR: "copy_from_user_overflow" [fs/binfmt_misc.ko] undefined!
>>>> >> make[5]: *** [__modpost] Error 1
>>>> >> make[4]: *** [modules] Error 2
>>>> >> make[4]: *** Waiting for unfinished jobs....
>>>> >> Â RELOCS Âarch/x86/boot/compressed/vmlinux.relocs
>>>> >> Â GZIP Â Âarch/x86/boot/compressed/vmlinux.bin.gz
>>>> >> Â MKPIGGY arch/x86/boot/compressed/piggy.S
>>>> >> Â AS Â Â Âarch/x86/boot/compressed/piggy.o
>>>> >> Â LD Â Â Âarch/x86/boot/compressed/vmlinux
>>>> >> Â ZOFFSET arch/x86/boot/zoffset.h
>>>> >> Â OBJCOPY arch/x86/boot/vmlinux.bin
>>>> >> Â AS Â Â Âarch/x86/boot/header.o
>>>> >> Â LD Â Â Âarch/x86/boot/setup.elf
>>>> >> Â OBJCOPY arch/x86/boot/setup.bin
>>>> >> Â BUILD Â arch/x86/boot/bzImage
>>>> >> Setup is 15596 bytes (padded to 15872 bytes).
>>>> >> System is 2471 kB
>>>> >> CRC eb598167
>>>> >> Kernel: arch/x86/boot/bzImage is ready Â(#1)
>>>> >> make[3]: *** [sub-make] Error 2
>>>> >> make[2]: *** [all] Error 2
>>>> >>
>>>> >> I have these binfmt kernel-config options set:
>>>> >>
>>>> >> CONFIG_BINFMT_ELF=y
>>>> >> # CONFIG_BINFMT_AOUT is not set
>>>> >> CONFIG_BINFMT_MISC=m
>>>> >
>>>> > How does someone turn off this error message?
>>>> >
>>>> > I have:
>>>> > # CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is not set
>>>> > # CONFIG_STRICT_DEVMEM is not set
>>>> >
>>>> > and I still cannot get this error to go away (on x86_64).
>>>> >
>>>> >
>>>> > ---
>>>> > ~Randy
>>>> > *** Remember to use Documentation/SubmitChecklist when testing your code ***
>>>> >
>>>>
>>>> Can you say with which linux-next version you saw this first?
>>>> My last version was next-20110722 (which was OK).
>>>
>>> It looks like 2011-0727 has lots of these errors in my randconfig builds,
>>> but I can't say that they are all incorrect, so it's not very conclusive.
>>>
>>> ---
>>> ~Randy
>>> *** Remember to use Documentation/SubmitChecklist when testing your code ***
>>>
>>
>> I can confirm next-20110726 is fine.
>>
>> # egrep 'BINFMT|DEBUG_STRICT_USER_COPY_CHECKS|STRICT_DEVMEM'
>> /boot/config-3.0.0-next20110726.3-686-small
>> CONFIG_BINFMT_ELF=y
>> CONFIG_BINFMT_AOUT=m
>> CONFIG_BINFMT_MISC=m
>> CONFIG_STRICT_DEVMEM=y
>> # CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is not set
>>
>> So, the binfmt_misc culprit was introduced between next-20110726
>> (good) and next-20110727 (bad).
>> I'll try to look into the diff, but can't promise.
>>
>> - Sedat -
>>
>
> [ CCing all people from 0416 patch ]
>
> OK, here a quick review and looking for suspicious commits:
>
> $ git format-patch next-20110726..next-20110727
>
> 487 patches in total.
>
> $ grep copy_from_user_overflow -nr *.patch
>
> 0389-x86_64-allmodconfig.patch
> 0414-Enabling-DEBUG_STRICT_USER_COPY_CHECKS-causes-the-fo.patch
> 0415-Strict-user-copy-checks-are-only-really-supported-on.patch
> 0416-The-help-text-for-this-config-is-duplicated-across-t.patch
>
> 0416 has thrown out...
>
> -void copy_from_user_overflow(void)
> -{
> - Â Â Â WARN(1, "Buffer overflow detected!\n");
> -}
> -EXPORT_SYMBOL(copy_from_user_overflow);
>
> ...and consilidated that in...
>
> --- /dev/null
> +++ b/lib/usercopy.c
> @@ -0,0 +1,8 @@
> +#include <linux/module.h>
> +#include <linux/bug.h>
> +
> +void copy_from_user_overflow(void)
> +{
> + Â Â Â WARN(1, "Buffer overflow detected!\n");
> +}
> +EXPORT_SYMBOL(copy_from_user_overflow);
>
> ...BUT builds usercopy.o only on
> CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS...
>
> -- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -14,6 +14,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \
> Â Â Â Â proportions.o prio_heap.o ratelimit.o show_mem.o \
> Â Â Â Â is_single_threaded.o plist.o decompress.o find_next_bit.o
>
> +lib-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o
> Âlib-$(CONFIG_MMU) += ioremap.o
> Âlib-$(CONFIG_SMP) += cpumask.o
>
> So, I can rebuild next-201107{27,28} with
> CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS=y and look again if the
> build-breakage in binfmt_misc is gone.
>
> Any comments from x86 folk?
>
> - Sedat -
>

I was able to compile next-20110728 by reverting:

commit ab3b49d018924085e5d949c1af53fae0da9a8d94
"The help text for this config is duplicated across the x86, parisc,
and s390 Kconfig.debug files."

The revert-patch is attached, also my kernel-config.

Randy, can you test with it for x86_64, please?
Thanks in advance.

- Sedat -

Attachment: 0001-Revert-The-help-text-for-this-config-is-duplicated-a.patch
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Attachment: config-3.0.0-next20110728.4-686-small
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