From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751544Ab1HHTLI (ORCPT ); Mon, 8 Aug 2011 15:11:08 -0400 Received: from oproxy5-pub.bluehost.com ([67.222.38.55]:32902 "HELO oproxy5-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750843Ab1HHTLF (ORCPT ); Mon, 8 Aug 2011 15:11:05 -0400 Date: Mon, 8 Aug 2011 12:11:04 -0700 From: Randy Dunlap To: Ben Greear Cc: gregkh@suse.de, linux-kernel Subject: Re: 3.0.1 compile error on Fedora 15 Message-Id: <20110808121104.5a233da4.rdunlap@xenotime.net> In-Reply-To: <4E403121.8080402@candelatech.com> References: <4E402E5F.5010600@candelatech.com> <20110808115238.b19b293e.rdunlap@xenotime.net> <4E403121.8080402@candelatech.com> Organization: YPO4 X-Mailer: Sylpheed 2.7.1 (GTK+ 2.16.6; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Identified-User: {1807:box742.bluehost.com:xenotime:xenotime.net} {sentby:smtp auth 50.53.38.135 authed with rdunlap@xenotime.net} Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ‘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? 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. > 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 ***