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Groups > linux.kernel > #1723994 > unrolled thread

linux-next: build failure after merge of the akpm-current tree

Started byStephen Rothwell <sfr@canb.auug.org.au>
First post2017-08-31 10:30 +0200
Last post2017-09-06 14:40 +0200
Articles 3 — 2 participants

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  linux-next: build failure after merge of the akpm-current tree Stephen Rothwell <sfr@canb.auug.org.au> - 2017-08-31 10:30 +0200
    [PATCH] string.h: un-fortify memcpy_and_pad Martin Wilck <mwilck@suse.com> - 2017-09-06 14:40 +0200
    Re: linux-next: build failure after merge of the akpm-current tree Martin Wilck <mwilck@suse.com> - 2017-09-06 14:40 +0200

#1723994 — linux-next: build failure after merge of the akpm-current tree

FromStephen Rothwell <sfr@canb.auug.org.au>
Date2017-08-31 10:30 +0200
Subjectlinux-next: build failure after merge of the akpm-current tree
Message-ID<ukt1o-3fk-23@gated-at.bofh.it>
Hi Andrew,

After merging the akpm-current tree, today's linux-next build (arm
multi_v7_defconfig) failed like this:

In file included from /home/sfr/next/next/include/uapi/linux/uuid.h:21:0,
                 from /home/sfr/next/next/include/linux/uuid.h:19,
                 from /home/sfr/next/next/include/linux/mod_devicetable.h:12,
                 from /home/sfr/next/next/scripts/mod/devicetable-offsets.c:2:
/home/sfr/next/next/include/linux/string.h: In function 'memcpy_and_pad':
/home/sfr/next/next/include/linux/string.h:450:3: error: implicit declaration of function 'fortify_panic' [-Werror=implicit-function-declaration]
   fortify_panic(__func__);
   ^

Caused by commit

  9b04e51112ba ("fortify: use WARN instead of BUG for now")

interacting with commit

  01f33c336e2d ("string.h: add memcpy_and_pad()")

from the block tree.

I have applied the following merge fix patch:

From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Thu, 31 Aug 2017 18:13:43 +1000
Subject: [PATCH] fortify: use WARN instead of BUG for now fix

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
 include/linux/string.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index edd2b6154b80..e3b713114732 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -447,7 +447,7 @@ __FORTIFY_INLINE void memcpy_and_pad(void *dest, size_t dest_len,
 			__read_overflow3();
 	}
 	if (dest_size < dest_len)
-		fortify_panic(__func__);
+		fortify_overflow(__func__);
 	if (dest_len > count) {
 		memcpy(dest, src, count);
 		memset(dest + count, pad,  dest_len - count);
-- 
2.13.2

-- 
Cheers,
Stephen Rothwell

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#1727393 — [PATCH] string.h: un-fortify memcpy_and_pad

FromMartin Wilck <mwilck@suse.com>
Date2017-09-06 14:40 +0200
Subject[PATCH] string.h: un-fortify memcpy_and_pad
Message-ID<umHMC-1JN-3@gated-at.bofh.it>
In reply to#1723994
The way I'd implemented the new helper memcpy_and_pad  with
__FORTIFY_INLINE caused compiler warnings for certain kernel
configurations.

This helper is only used in a single place at this time, and thus
doesn't benefit much from fortification. So simplify the code
by dropping fortification support for now.

Fixes: 01f33c336e2d "string.h: add memcpy_and_pad()"
Signed-off-by: Martin Wilck <mwilck@suse.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>

---
 include/linux/string.h | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index e1eeb0a8a9693..54d21783e18dd 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -434,20 +434,9 @@ __FORTIFY_INLINE char *strcpy(char *p, const char *q)
  * @count: The number of bytes to copy
  * @pad: Character to use for padding if space is left in destination.
  */
-__FORTIFY_INLINE void memcpy_and_pad(void *dest, size_t dest_len,
-				     const void *src, size_t count, int pad)
+static inline void memcpy_and_pad(void *dest, size_t dest_len,
+				  const void *src, size_t count, int pad)
 {
-	size_t dest_size = __builtin_object_size(dest, 0);
-	size_t src_size = __builtin_object_size(src, 0);
-
-	if (__builtin_constant_p(dest_len) && __builtin_constant_p(count)) {
-		if (dest_size < dest_len && dest_size < count)
-			__write_overflow();
-		else if (src_size < dest_len && src_size < count)
-			__read_overflow3();
-	}
-	if (dest_size < dest_len)
-		fortify_panic(__func__);
 	if (dest_len > count) {
 		memcpy(dest, src, count);
 		memset(dest + count, pad,  dest_len - count);
-- 
2.14.0

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#1727396

FromMartin Wilck <mwilck@suse.com>
Date2017-09-06 14:40 +0200
Message-ID<umHMC-1JN-13@gated-at.bofh.it>
In reply to#1723994
Hello Stephen,

On Thu, 2017-08-31 at 18:21 +1000, Stephen Rothwell wrote:
> Hi Andrew,
> 
> After merging the akpm-current tree, today's linux-next build (arm
> multi_v7_defconfig) failed like this:
> 
> In file included from
> /home/sfr/next/next/include/uapi/linux/uuid.h:21:0,
>                  from /home/sfr/next/next/include/linux/uuid.h:19,
>                  from
> /home/sfr/next/next/include/linux/mod_devicetable.h:12,
>                  from /home/sfr/next/next/scripts/mod/devicetable-
> offsets.c:2:
> /home/sfr/next/next/include/linux/string.h: In function
> 'memcpy_and_pad':
> /home/sfr/next/next/include/linux/string.h:450:3: error: implicit
> declaration of function 'fortify_panic' [-Werror=implicit-function-
> declaration]
>    fortify_panic(__func__);
>    ^
> 
> Caused by commit
> 
>   9b04e51112ba ("fortify: use WARN instead of BUG for now")
> 
> interacting with commit
> 
>   01f33c336e2d ("string.h: add memcpy_and_pad()")
> 
> from the block tree.
> 
> I have applied the following merge fix patch:
> 
> From: Stephen Rothwell <sfr@canb.auug.org.au>
> Date: Thu, 31 Aug 2017 18:13:43 +1000
> Subject: [PATCH] fortify: use WARN instead of BUG for now fix
> 
> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
> ---
>  include/linux/string.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/string.h b/include/linux/string.h
> index edd2b6154b80..e3b713114732 100644
> --- a/include/linux/string.h
> +++ b/include/linux/string.h
> @@ -447,7 +447,7 @@ __FORTIFY_INLINE void memcpy_and_pad(void *dest,
> size_t dest_len,
>  			__read_overflow3();
>  	}
>  	if (dest_size < dest_len)
> -		fortify_panic(__func__);
> +		fortify_overflow(__func__);
>  	if (dest_len > count) {
>  		memcpy(dest, src, count);
>  		memset(dest + count, pad,  dest_len - count);
> -- 
> 2.13.2

Arnd Bergmann spotted another problem with that patch. I decided to rip
out the "fortify" related code. I'll send a patch in a follow-up email.

Regards,
Martin

-- 
Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)

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