From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] lib: __builtin_object_size should accept void * Date: Thu, 24 Nov 2016 05:28:34 +0200 Message-ID: <20161124052744-mutt-send-email-mst@kernel.org> References: <1479932572-12543-1-git-send-email-mst@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34720 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750749AbcKXDaF (ORCPT ); Wed, 23 Nov 2016 22:30:05 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Christopher Li Cc: Josh Triplett , Linux-Sparse On Thu, Nov 24, 2016 at 08:16:24AM +0800, Christopher Li wrote: > A similar patch has been applied: > > Chris > > commit f2bf519e1da89779380fd781c0eb28aae415979d > Author: Lance Richardson > Date: Wed Sep 21 10:13:58 2016 -0400 > > sparse: update __builtin_object_size() prototype > > Sparse emits a large number of warnings for the linux kernel source > tree of the form: > ./arch/x86/include/asm/uaccess.h:735:18: \ > warning: incorrect type in argument 1 (different modifiers) > ./arch/x86/include/asm/uaccess.h:735:18: expected void * > ./arch/x86/include/asm/uaccess.h:735:18: got void const *from > > Fix by making the first parameter to __builtin_object_size() > type "const void *" instead of "void *", which is consistent with GCC > behavior (the prototype for this builtin in GCC documentation is evidently > incorrect). > > Signed-off-by: Lance Richardson > Acked-by: Luc Van Oostenryck > Signed-off-by: Christopher Li Doesn't seem to be pushed yet - at least I don't see it in master on git://git.kernel.org/pub/scm/devel/sparse/sparse.git > diff --git a/lib.c b/lib.c > index d5b56b0..2d66aa0 100644 > --- a/lib.c > +++ b/lib.c > @@ -888,7 +888,7 @@ void declare_builtin_functions(void) > add_pre_buffer("extern long double __builtin_nanl(const char *);\n"); > > /* And some __FORTIFY_SOURCE ones.. */ > - add_pre_buffer ("extern __SIZE_TYPE__ > __builtin_object_size(void *, int);\n"); > + add_pre_buffer ("extern __SIZE_TYPE__ > __builtin_object_size(const void *, int);\n"); > add_pre_buffer ("extern void * __builtin___memcpy_chk(void *, > const void *, __SIZE_TYPE__, __SIZE_TYPE__);\n"); > add_pre_buffer ("extern void * __builtin___memmove_chk(void *, > const void *, __SIZE_TYPE__, __SIZE_TYPE__);\n"); > add_pre_buffer ("extern void * __builtin___mempcpy_chk(void *, > const void *, __SIZE_TYPE__, __SIZE_TYPE__);\n"); > > > > On Thu, Nov 24, 2016 at 4:24 AM, Michael S. Tsirkin wrote: > > I'm seeing these warnings with current Linux: > > ./arch/x86/include/asm/uaccess.h:705:18: warning: incorrect type in argument 1 (different modifiers) > > ./arch/x86/include/asm/uaccess.h:705:18: expected void * > > ./arch/x86/include/asm/uaccess.h:705:18: got void const *from > > > > Because of this code: > > > > static __always_inline unsigned long __must_check > > copy_to_user(void __user *to, const void *from, unsigned long n) > > { > > int sz = __compiletime_object_size(from); > > > > ... > > } > > > > where we have > > > > # define __compiletime_object_size(obj) __builtin_object_size(obj, 0) > > > > to fix, mark the argument as const void *. > > > > Signed-off-by: Michael S. Tsirkin > > --- > > > > Sorry if this has already been reported/fixed. > > > > lib.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/lib.c b/lib.c > > index d5b56b0..2d66aa0 100644 > > --- a/lib.c > > +++ b/lib.c > > @@ -888,7 +888,7 @@ void declare_builtin_functions(void) > > add_pre_buffer("extern long double __builtin_nanl(const char *);\n"); > > > > /* And some __FORTIFY_SOURCE ones.. */ > > - add_pre_buffer ("extern __SIZE_TYPE__ __builtin_object_size(void *, int);\n"); > > + add_pre_buffer ("extern __SIZE_TYPE__ __builtin_object_size(const void *, int);\n"); > > add_pre_buffer ("extern void * __builtin___memcpy_chk(void *, const void *, __SIZE_TYPE__, __SIZE_TYPE__);\n"); > > add_pre_buffer ("extern void * __builtin___memmove_chk(void *, const void *, __SIZE_TYPE__, __SIZE_TYPE__);\n"); > > add_pre_buffer ("extern void * __builtin___mempcpy_chk(void *, const void *, __SIZE_TYPE__, __SIZE_TYPE__);\n"); > > -- > > MST > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-sparse" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html