Re: [PATCH] Consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECK

From: Arjan van de Ven
Date: Wed Feb 27 2013 - 17:56:16 EST


On 2/27/2013 2:45 PM, Stephen Rothwell wrote:
Hi all,

On Wed, 27 Feb 2013 14:19:16 -0800 "H. Peter Anvin" <hpa@xxxxxxxxx> wrote:

Although some of the cases I have seen being flagged as "false
positives" have been real bugs.

[hijacking the thread :-)]

I have been getting this warning for a very long time ( which would be an
error if CONFIG_DEBUG_STRICT_USER_COPY_CHECK was set):

i386 defconfig
i386-linux-gcc (GCC) 4.6.3

In file included from arch/x86/include/asm/uaccess.h:537:0,
from include/linux/uaccess.h:5,
from include/linux/highmem.h:8,
from include/linux/pagemap.h:10,
from fs/binfmt_misc.c:27:
arch/x86/include/asm/uaccess_32.h: In function 'parse_command.part.2':
arch/x86/include/asm/uaccess_32.h:211:26: warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct [enabled by default]



http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35392

the gcc folks finally fixed that one it seems

(but while there are some false positives, esp with older gcc, the majority were real originally.. just those all got fixed)


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