Re: 3.0.1 compile error on Fedora 15

[Ben Greear <greearb@candelatech.com>]

On 08/08/2011 11:52 AM, Randy Dunlap wrote:
> On Mon, 08 Aug 2011 11:43:43 -0700 Ben Greear wrote:
>
>> [greearb@t60-ben linux-3.0.p4s]$ make
>> make -C /home/greearb/git/linux-3.0.dev.y O=/home/greearb/kernel/2.6/linux-3.0.p4s/.
>>     Using /home/greearb/git/linux-3.0.dev.y as source for kernel
>>     GEN     /home/greearb/kernel/2.6/linux-3.0.p4s/Makefile
>>     CHK     include/linux/version.h
>>     CHK     include/generated/utsrelease.h
>>     CALL    /home/greearb/git/linux-3.0.dev.y/scripts/checksyscalls.sh
>>     CHK     include/generated/compile.h
>>     CC      fs/binfmt_misc.o
>> In file included from /home/greearb/git/linux-3.0.dev.y/arch/x86/include/asm/uaccess.h:570:0,
>>                    from /home/greearb/git/linux-3.0.dev.y/include/linux/uaccess.h:5,
>>                    from /home/greearb/git/linux-3.0.dev.y/include/linux/highmem.h:7,
>>                    from /home/greearb/git/linux-3.0.dev.y/include/linux/pagemap.h:10,
>>                    from /home/greearb/git/linux-3.0.dev.y/fs/binfmt_misc.c:26:
>> /home/greearb/git/linux-3.0.dev.y/arch/x86/include/asm/uaccess_32.h: In function ‘parse_command.part.0’:
>> /home/greearb/git/linux-3.0.dev.y/arch/x86/include/asm/uaccess_32.h:211:26: error: call to ‘copy_from_user_overflow’ declared with attribute error:
>> copy_from_user() buffer size is not provably correct
>> make[3]: *** [fs/binfmt_misc.o] Error 1
>> make[2]: *** [fs] Error 2
>> make[1]: *** [sub-make] Error 2
>> make: *** [all] Error 2
>> [greearb@t60-ben linux-3.0.p4s]$
>>
>>
>> The code in question is below.  Is this missing an assignment to n
>> in the else branch?
>>
>> static inline unsigned long __must_check copy_from_user(void *to,
>>                                             const void __user *from,
>>                                             unsigned long n)
>> {
>>           int sz = __compiletime_object_size(to);
>>
>>           if (likely(sz == -1 || sz>= n))
>>                   n = _copy_from_user(to, from, n);
>>           else
>>                   copy_from_user_overflow();
>>
>>           return n;
>> }
>
>
> Do you have this kconfig option enabled?
> CONFIG_DEBUG_STRICT_USER_COPY_CHECKS=y
>
> If so, you should get the error that you reported.
> If not, then you need a patch like the one below (which has been posted
> by other people several times -- might need to be added to -stable):

I do have that enabled.   I'm slightly confused by your response above:

Do I need to disable the check AND apply the patch below, or just disable
the check, or just apply the patch and leave the check enabled?

Thanks,
Ben

>
>
> ---
>   lib/Makefile |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-next-20110728.orig/lib/Makefile
> +++ linux-next-20110728/lib/Makefile
> @@ -14,7 +14,7 @@ lib-y := ctype.o string.o vsprintf.o cmd
>   	 proportions.o prio_heap.o ratelimit.o show_mem.o \
>   	 is_single_threaded.o plist.o decompress.o find_next_bit.o
>
> -lib-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o
> +obj-$(CONFIG_ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS) += usercopy.o
>   lib-$(CONFIG_MMU) += ioremap.o
>   lib-$(CONFIG_SMP) += cpumask.o
>


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com