Re: 3.0.1 compile error on Fedora 15

Randy Dunlap
2011-08-08T18:52:41Z

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):

---
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