Re: [PATCH] [PERF] (Userspace Tools) Fix a compilation error with -fstack-protector and -Werror

[Frederic Weisbecker <fweisbec@gmail.com>]

On Tue, Oct 19, 2010 at 03:06:41AM +0300, Brian Gitonga Marete wrote:
> On Tue, Oct 19, 2010 at 2:38 AM, Frederic Weisbecker <fweisbec@gmail.com> wrote:
> > On Tue, Oct 19, 2010 at 02:24:00AM +0300, Brian Gitonga Marete wrote:
> >> The following patch fixes compilation of the perf user-space tools on,
> >> for example, gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4) . It should not
> >> break anything else.
> >
> >
> >
> > Hi,
> >
> > What kind of warning have you encountered and why it fixes it?
> > Can you describe that in your changelog?
> >
> 
> Hello Frederic,
> 
> Some versions of gcc, e.g. gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4), have
> the (default) minimum size of buffers protected by `-fstack-protector' set
> to 8. But in perf, there exist much smaller automatic buffers.
> 
> This in combination with the -fstack-protector-all, -Werror and
> -Wstack-protector causes the compile to fail for such a compiler.
> 
> The error encountered with the above-mentioned compiler is:
> 
> gcc -o util/ui/util.o -c -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6
> -D_FORTIFY_SOURCE=2 -Wformat -Wformat-security -Wformat-y2k -Wshadow
> -Winit-self -Wpacked -Wredundant-decls -Wstack-protector
> -Wstrict-aliasing=3 -Wswitch-default -Wswitch-enum -Wno-system-headers
> -Wundef -Wvolatile-register-var -Wwrite-strings -Wbad-function-cast
> -Wmissing-declarations -Wmissing-prototypes -Wnested-externs
> -Wold-style-definition -Wstrict-prototypes
> -Wdeclaration-after-statement  -fstack-protector-all
> -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -Iutil/include
> -Iarch/x86/include -DLIBELF_NO_MMAP -I/usr/include/elfutils
> -DDWARF_SUPPORT -I/usr/include/slang -DSHA1_HEADER='<openssl/sha.h>'
> util/ui/util.c
> cc1: warnings being treated as errors
> util/ui/util.c: In function ‘ui__dialog_yesno’:
> util/ui/util.c:110: error: not protecting function: no buffer at least
> 8 bytes long


Doh! So that was the reason of this warning. Yeah looks like a right fix.
And that fixes the issue for me.

Tested-by: Frederic Weisbecker <fweisbec@gmail.com>

Thanks!


> 
> Signed-off-by: Brian Gitonga Marete <marete@toshnix.com>
> ---
>  tools/perf/Makefile |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 1950e19..64eb2ea 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -288,7 +288,7 @@ endif
>  -include feature-tests.mak
> 
>  ifeq ($(call try-cc,$(SOURCE_HELLO),-Werror -fstack-protector-all),y)
> -	CFLAGS := $(CFLAGS) -fstack-protector-all
> +	CFLAGS := $(CFLAGS) -fstack-protector-all --param ssp-buffer-size=1
>  endif
> 
> 
> -- 
> 1.6.0.4
> 
> 
> -- 
> Brian Gitonga Marete
> Toshnix Systems
> Tel: +254722151590