lkml.org 
[lkml]   [2021]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] string: uninline memcpy_and_pad
From
Date
On 11/2/21 12:56 AM, Geert Uytterhoeven wrote:
> Hi Günter,
>
> Thanks for your patch!
>
> On Tue, Nov 2, 2021 at 5:30 AM Guenter Roeck <linux@roeck-us.net> wrote:
>> When building m68k:allmodconfig, recent versions of gcc generate the
>> following error if the length of UTS_RELEASE is less than 8 bytes.
>>
>> In function 'memcpy_and_pad',
>> inlined from 'nvmet_execute_disc_identify' at
>> drivers/nvme/target/discovery.c:268:2:
>> arch/m68k/include/asm/string.h:72:25: error:
>> '__builtin_memcpy' reading 8 bytes from a region of size 7
>>
>> Discussions around the problem suggest that this only happens if an
>> architecture does not provide strlen(), if -ffreestanding is provided as
>> compiler option, and if CONFIG_FORTIFY_SOURCE=n. All of this is the case
>> for m68k. The exact reasons are unknown, but seem to be related to the
>> ability of the compiler to evaluate the return value of strlen() and
>> the resulting execution flow in memcpy_and_pad(). It would be possible
>> to work around the problem by using sizeof(UTS_RELEASE) instead of
>> strlen(UTS_RELEASE), but that would only postpone the problem until the
>> function is called in a similar way. Uninline memcpy_and_pad() instead
>> to solve the problem for good.
>>
>> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
>> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>
> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
>> include/linux/string.h | 19 ++-----------------
>> lib/string.c | 19 +++++++++++++++++++
>> 2 files changed, 21 insertions(+), 17 deletions(-)
>
> Given this now conflicts with commit cfecea6ead5f1588 ("lib/string:
> Move helper functions out of string.c"). perhaps you should move this
> to lib/string_helpers.c when respinning?
>

Will do.

Thanks,
Guenter

\
 
 \ /
  Last update: 2021-11-02 15:21    [W:0.039 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site