Re: 3.0.1 compile error on Fedora 15
From: Ben Greear
Date: Mon Aug 08 2011 - 15:33:14 EST
On 08/08/2011 12:11 PM, Randy Dunlap wrote:
On Mon, 08 Aug 2011 11:55:29 -0700 Ben Greear wrote:
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 âparse_command.part.0â:
/home/greearb/git/linux-3.0.dev.y/arch/x86/include/asm/uaccess_32.h:211:26: error: call to âcopy_from_user_overflowâ 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?
Hm, I guess I'm confused also. The patch only applies to linux-next,
not to 3.0.x.
The patch below is needed (in linux-next) to fix a build
error when CONFIG_DEBUG_STRICT_USER_COPY_CHECKS is not enabled.
When you do have CONFIG_DEBUG_STRICT_USER_COPY_CHECKS, the build error is
the correct result. AFAIK. So it looks to me like you should either
disable the kconfig option or fix the code in fs/binfmt_misc.c.
I would do the former -- depending on your use case.
I can disable the check, but I hope someone fixes the real problem
and sends the patch to stable. Seems a bit lame that we have compile
errors in stable series...
Thanks,
Ben
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
--
---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***
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--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc http://www.candelatech.com
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