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

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

[Brian Gitonga Marete]

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.

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

-- 
Brian Gitonga Marete
Toshnix Systems
Tel: +254722151590

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

[Frederic Weisbecker]

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?

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
> 
> -- 
> Brian Gitonga Marete
> Toshnix Systems
> Tel: +254722151590
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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Re: [PATCH] [PERF] (Userspace Tools) Fix a compilation error with -fstack-protector and -Werror

[Brian Gitonga Marete]

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

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

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

[Frederic Weisbecker]

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

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

[Ingo Molnar]

* Brian Gitonga Marete <marete@toshnix.com> 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.

Hm, it's this code:

        /* newtWinChoice should really be accepting const char pointers... */
        char yes[] = "Yes", no[] = "No";
        return newtWinChoice(NULL, yes, no, (char *)msg) == 1;

I.e. the code is messy and GCC is right to warn about it. Hence it would be somewhat 
bad to actually remove the warning that pointed out some dodgy piece of code.

Even if marking it const doesnt work due to the external libnewt API, we could at 
least put 'yes' and 'no' into file scope and mark them static?

	Ingo

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

[Américo Wang]

On Tue, Oct 19, 2010 at 08:40:00AM +0200, Ingo Molnar wrote:
>
>* Brian Gitonga Marete <marete@toshnix.com> 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.
>
>Hm, it's this code:
>
>        /* newtWinChoice should really be accepting const char pointers... */
>        char yes[] = "Yes", no[] = "No";
>        return newtWinChoice(NULL, yes, no, (char *)msg) == 1;
>
>I.e. the code is messy and GCC is right to warn about it. Hence it would be somewhat 
>bad to actually remove the warning that pointed out some dodgy piece of code.

Agreed.

>
>Even if marking it const doesnt work due to the external libnewt API, we could at 
>least put 'yes' and 'no' into file scope and mark them static?
>

How about making ui__dialog_yesno() a macro? ;) Like:

#define ui__dialog_yesno(msg) \
	({newWinChoice(NULL, "Yes", "No", (char *)(msg)) == 1;})

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

[Brian Gitonga Marete]

On Tue, Oct 19, 2010 at 9:40 AM, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Brian Gitonga Marete <marete@toshnix.com> 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.
>
> Hm, it's this code:
>
>        /* newtWinChoice should really be accepting const char pointers... */
>        char yes[] = "Yes", no[] = "No";
>        return newtWinChoice(NULL, yes, no, (char *)msg) == 1;
>
> I.e. the code is messy and GCC is right to warn about it. Hence it would be somewhat
> bad to actually remove the warning that pointed out some dodgy piece of code.
>
> Even if marking it const doesnt work due to the external libnewt API, we could at
> least put 'yes' and 'no' into file scope and mark them static?

OK. Now that I actually look closely at that fragment I can see its
useless to create the automatic arrays. Local string literals would
also work (i.e. just pass `"Yes"' and `"No"' to newtWinChoice). But
can also do what you suggested if it is anticipated that they will be
used somewhere else within the file at some other time -- Currently
they are not.

Thanks.
-- 
Brian Gitonga Marete
Toshnix Systems
Tel: +254722151590

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

[Brian Gitonga Marete]

On Tue, Oct 19, 2010 at 2:12 PM, Brian Gitonga Marete
<marete@toshnix.com> wrote:
> On Tue, Oct 19, 2010 at 9:40 AM, Ingo Molnar <mingo@elte.hu> wrote:
>>
>> * Brian Gitonga Marete <marete@toshnix.com> 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.
>>
>> Hm, it's this code:
>>
>>        /* newtWinChoice should really be accepting const char pointers... */
>>        char yes[] = "Yes", no[] = "No";
>>        return newtWinChoice(NULL, yes, no, (char *)msg) == 1;
>>
>> I.e. the code is messy and GCC is right to warn about it. Hence it would be somewhat
>> bad to actually remove the warning that pointed out some dodgy piece of code.
>>
>> Even if marking it const doesnt work due to the external libnewt API, we could at
>> least put 'yes' and 'no' into file scope and mark them static?
>
> OK. Now that I actually look closely at that fragment I can see its
> useless to create the automatic arrays. Local string literals would
> also work (i.e. just pass `"Yes"' and `"No"' to newtWinChoice). But
> can also do what you suggested if it is anticipated that they will be
> used somewhere else within the file at some other time -- Currently
> they are not.
>

Oops. Sorry. What I suggested won't work because of the
-Wwrite-strings default option. Which actually makes me understand why
the original author of the code made it the way it is. Your suggestion
of file-scope, static does solve the problem.


-- 
Brian Gitonga Marete
Toshnix Systems
Tel: +254722151590

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

[Brian Gitonga Marete]

On Tue, Oct 19, 2010 at 2:33 PM, Brian Gitonga Marete
<marete@toshnix.com> wrote:
> On Tue, Oct 19, 2010 at 2:12 PM, Brian Gitonga Marete
> <marete@toshnix.com> wrote:
>> On Tue, Oct 19, 2010 at 9:40 AM, Ingo Molnar <mingo@elte.hu> wrote:
>>>
>>> * Brian Gitonga Marete <marete@toshnix.com> 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.
>>>
>>> Hm, it's this code:
>>>
>>>        /* newtWinChoice should really be accepting const char pointers... */
>>>        char yes[] = "Yes", no[] = "No";
>>>        return newtWinChoice(NULL, yes, no, (char *)msg) == 1;
>>>
>>> I.e. the code is messy and GCC is right to warn about it. Hence it would be somewhat
>>> bad to actually remove the warning that pointed out some dodgy piece of code.
>>>
>>> Even if marking it const doesnt work due to the external libnewt API, we could at
>>> least put 'yes' and 'no' into file scope and mark them static?
>>
>> OK. Now that I actually look closely at that fragment I can see its
>> useless to create the automatic arrays. Local string literals would
>> also work (i.e. just pass `"Yes"' and `"No"' to newtWinChoice). But
>> can also do what you suggested if it is anticipated that they will be
>> used somewhere else within the file at some other time -- Currently
>> they are not.
>>
>
> Oops. Sorry. What I suggested won't work because of the
> -Wwrite-strings default option. Which actually makes me understand why
> the original author of the code made it the way it is. Your suggestion
> of file-scope, static does solve the problem.
>

As indeed does Americo's suggestion above.


-- 
Brian Gitonga Marete
Toshnix Systems
Tel: +254722151590

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

[Ingo Molnar]

* Brian Gitonga Marete <marete@toshnix.com> wrote:

> > OK. Now that I actually look closely at that fragment I can see its useless to 
> > create the automatic arrays. Local string literals would also work (i.e. just 
> > pass `"Yes"' and `"No"' to newtWinChoice). But can also do what you suggested if 
> > it is anticipated that they will be used somewhere else within the file at some 
> > other time -- Currently they are not.
> 
> Oops. Sorry. What I suggested won't work because of the -Wwrite-strings default 
> option. Which actually makes me understand why the original author of the code 
> made it the way it is. Your suggestion of file-scope, static does solve the 
> problem.

Btw., -Wwrite-strings has proven to be a really useful warning in practice, in that 
it ensured that we propagate string immutability/const-ness as widely as possible. 
This resulted is cleaner perf code in the long run.

Here we cannot fix the Newt prototype (it's an existing library outside of our 
control) to take a const so we have to do the (mild) workaround of moving it to file 
scope. (if this becomes common then we'd have to re-evaluate the use of this 
warning)

I think Arnaldo has plans to get rid of the libnewt dependency altogether - that 
might be a fix too.

Thanks,

	Ingo

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

[Arnaldo Carvalho de Melo]

Em Tue, Oct 19, 2010 at 01:49:04PM +0200, Ingo Molnar escreveu:
> 
> * Brian Gitonga Marete <marete@toshnix.com> wrote:
> 
> > > OK. Now that I actually look closely at that fragment I can see its useless to 
> > > create the automatic arrays. Local string literals would also work (i.e. just 
> > > pass `"Yes"' and `"No"' to newtWinChoice). But can also do what you suggested if 
> > > it is anticipated that they will be used somewhere else within the file at some 
> > > other time -- Currently they are not.
> > 
> > Oops. Sorry. What I suggested won't work because of the -Wwrite-strings default 
> > option. Which actually makes me understand why the original author of the code 
> > made it the way it is. Your suggestion of file-scope, static does solve the 
> > problem.
> 
> Btw., -Wwrite-strings has proven to be a really useful warning in practice, in that 
> it ensured that we propagate string immutability/const-ness as widely as possible. 
> This resulted is cleaner perf code in the long run.
> 
> Here we cannot fix the Newt prototype (it's an existing library outside of our 
> control) to take a const so we have to do the (mild) workaround of moving it to file 
> scope. (if this becomes common then we'd have to re-evaluate the use of this 
> warning)
> 
> I think Arnaldo has plans to get rid of the libnewt dependency altogether - that 
> might be a fix too.

Yeah, but for now I'll just reap the results of this long discussion
about this issue. :)

- Arnaldo

[PATCH] Fix a compile error with -fstack-protector, -Wstack-protector and -Werror.

[Brian Gitonga Marete]

The following is as per Ingo's suggestion. Agains 2.6.36. Thanks.

In the function ui__dialog_yesno(), automatic buffers have to be used as long
as we are compiling perf with the -Wwrite-stings and -Werror options. This is because the
Newt library does not declare the string parameters in newtWinChoice() as
constant when it should.

But the automatic buffers are not large enough to benefit from ssp at least on some gcc versions, e.g. the one that comes with Ubuntu 9.0.4. This along with -Wstack-protector causes a compile warning which is turned into an error by
-Werror.

This patch works around this problem by making the buffers global and static.

Signed-off-by: Brian Gitonga Marete <marete@toshnix.com>
---
 tools/perf/util/ui/util.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/tools/perf/util/ui/util.c b/tools/perf/util/ui/util.c
index 04600e2..c7dc022 100644
--- a/tools/perf/util/ui/util.c
+++ b/tools/perf/util/ui/util.c
@@ -11,6 +11,9 @@
 #include "helpline.h"
 #include "util.h"
 
+static char yes[] = "Yes";
+static char no[] = "No";
+
 newtComponent newt_form__new(void);
 
 static void newt_form__set_exit_keys(newtComponent self)
@@ -109,6 +112,5 @@ out_destroy_form:
 bool ui__dialog_yesno(const char *msg)
 {
 	/* newtWinChoice should really be accepting const char pointers... */
-	char yes[] = "Yes", no[] = "No";
 	return newtWinChoice(NULL, yes, no, (char *)msg) == 1;
 }
-- 
1.7.1.1

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

[Eric Dumazet]

Le mardi 19 octobre 2010 à 11:11 -0200, Arnaldo Carvalho de Melo a
écrit :
> Em Tue, Oct 19, 2010 at 01:49:04PM +0200, Ingo Molnar escreveu:
> > 
> > * Brian Gitonga Marete <marete@toshnix.com> wrote:
> > 
> > > > OK. Now that I actually look closely at that fragment I can see its useless to 
> > > > create the automatic arrays. Local string literals would also work (i.e. just 
> > > > pass `"Yes"' and `"No"' to newtWinChoice). But can also do what you suggested if 
> > > > it is anticipated that they will be used somewhere else within the file at some 
> > > > other time -- Currently they are not.
> > > 
> > > Oops. Sorry. What I suggested won't work because of the -Wwrite-strings default 
> > > option. Which actually makes me understand why the original author of the code 
> > > made it the way it is. Your suggestion of file-scope, static does solve the 
> > > problem.
> > 
> > Btw., -Wwrite-strings has proven to be a really useful warning in practice, in that 
> > it ensured that we propagate string immutability/const-ness as widely as possible. 
> > This resulted is cleaner perf code in the long run.
> > 
> > Here we cannot fix the Newt prototype (it's an existing library outside of our 
> > control) to take a const so we have to do the (mild) workaround of moving it to file 
> > scope. (if this becomes common then we'd have to re-evaluate the use of this 
> > warning)
> > 
> > I think Arnaldo has plans to get rid of the libnewt dependency altogether - that 
> > might be a fix too.
> 
> Yeah, but for now I'll just reap the results of this long discussion
> about this issue. :)
> 

Hi Arnaldo

Sorry if I missed something, but current linux-2.6 tree has the problem.

Is the fix under control ?

Thanks !

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

[Arnaldo Carvalho de Melo]

Em Thu, Nov 11, 2010 at 11:25:35AM +0100, Eric Dumazet escreveu:
> Hi Arnaldo
> 
> Sorry if I missed something, but current linux-2.6 tree has the problem.
> 
> Is the fix under control ?

Ingo merged this while I'm away, its in tip/urgent.

commit a3da8e451321c31d88cebd12c234d0aac2a1cc35
Author: Cyrill Gorcunov <gorcunov@gmail.com>
Date:   Sat Nov 6 11:47:24 2010 +0300

    perf, ui: Eliminate stack-smashing protection compiler complaint


- Arnaldo

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

[Eric Dumazet]

Le jeudi 11 novembre 2010 à 12:05 -0500, Arnaldo Carvalho de Melo a
écrit :

> Ingo merged this while I'm away, its in tip/urgent.

So far so good ;)

Thanks !