Re: Building 4.14 LTS kernel with GCC 8

[Greg KH <greg@kroah.com>]

On Thu, Oct 11, 2018 at 11:12:38AM +0100, Ignat Korchagin wrote:
> On Thu, Oct 11, 2018 at 8:29 AM Greg KH <greg@kroah.com> wrote:
> 
> > Why is this last commit needed?
> 
> Without it I get the following compile error (Debian 9 with
> self-compiled GCC 8):
> 
> builtin-script.c: In function 'get_script_path':
> builtin-script.c:2139:20: error: '%s' directive writing up to 255
> bytes into a region of size between 0 and 4095
> [-Werror=format-overflow=]
>   sprintf(path, "%s/%s", base_path, dent->d_name);
>                     ^~
> In file included from /usr/include/stdio.h:938,
>                  from util/event.h:6,
>                  from util/debug.h:9,
>                  from builtin-script.c:6:
> /usr/include/x86_64-linux-gnu/bits/stdio2.h:33:10: note:
> '__builtin___sprintf_chk' output between 2 and 4352 bytes into a
> destination of size 4096
>    return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        __bos (__s), __fmt, __va_arg_pack ());
>        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> builtin-script.c:2139:20: error: '%s' directive writing up to 255
> bytes into a region of size between 0 and 4095
> [-Werror=format-overflow=]
>   sprintf(path, "%s/%s", base_path, dent->d_name);
>                     ^~
> In file included from /usr/include/stdio.h:938,
>                  from util/event.h:6,
>                  from util/debug.h:9,
>                  from builtin-script.c:6:
> /usr/include/x86_64-linux-gnu/bits/stdio2.h:33:10: note:
> '__builtin___sprintf_chk' output between 2 and 4352 bytes into a
> destination of size 4096
>    return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        __bos (__s), __fmt, __va_arg_pack ());
>        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> builtin-script.c: In function 'find_scripts':
> builtin-script.c:2139:20: error: '%s' directive writing up to 255
> bytes into a region of size between 0 and 4095
> [-Werror=format-overflow=]
>   sprintf(path, "%s/%s", base_path, dent->d_name);
>                     ^~
> In file included from /usr/include/stdio.h:938,
>                  from util/event.h:6,
>                  from util/debug.h:9,
>                  from builtin-script.c:6:
> /usr/include/x86_64-linux-gnu/bits/stdio2.h:33:10: note:
> '__builtin___sprintf_chk' output between 2 and 4352 bytes into a
> destination of size 4096
>    return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        __bos (__s), __fmt, __va_arg_pack ());
>        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> builtin-script.c:2139:20: error: '%s' directive writing up to 255
> bytes into a region of size between 0 and 4095
> [-Werror=format-overflow=]
>   sprintf(path, "%s/%s", base_path, dent->d_name);
>                     ^~
> In file included from /usr/include/stdio.h:938,
>                  from util/event.h:6,
>                  from util/debug.h:9,
>                  from builtin-script.c:6:
> /usr/include/x86_64-linux-gnu/bits/stdio2.h:33:10: note:
> '__builtin___sprintf_chk' output between 2 and 4352 bytes into a
> destination of size 4096
>    return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
>           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>        __bos (__s), __fmt, __va_arg_pack ());
>        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> cc1: all warnings being treated as errors

That's odd, given that the moved code is the same...

Oh well, I'll go queue it up, thanks,

greg k-h