[PATCH] perf-record: Check correct pid when forking

[PATCH] perf-record: Check correct pid when forking

[Borislav Petkov]

When forking the child to be traced, we should check the correct return
value from fork() and not a local variable which is otherwise unused.

Signed-off-by: Borislav Petkov <bp@alien8.de>
---
 tools/perf/builtin-record.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 9bc8905..dc3435e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -503,7 +503,6 @@ static int __cmd_record(int argc, const char **argv)
 {
 	int i, counter;
 	struct stat st;
-	pid_t pid = 0;
 	int flags;
 	int err;
 	unsigned long waking = 0;
@@ -572,7 +571,7 @@ static int __cmd_record(int argc, const char **argv)
 
 	if (forks) {
 		child_pid = fork();
-		if (pid < 0) {
+		if (child_pid < 0) {
 			perror("failed to fork");
 			exit(-1);
 		}
-- 
1.7.1


-- 
Regards/Gruss,
    Boris.

Re: [PATCH] perf-record: Check correct pid when forking

[Frederic Weisbecker]

On Mon, May 31, 2010 at 11:18:18PM +0200, Borislav Petkov wrote:
> When forking the child to be traced, we should check the correct return
> value from fork() and not a local variable which is otherwise unused.
> 
> Signed-off-by: Borislav Petkov <bp@alien8.de>
> ---
>  tools/perf/builtin-record.c |    3 +--
>  1 files changed, 1 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 9bc8905..dc3435e 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -503,7 +503,6 @@ static int __cmd_record(int argc, const char **argv)
>  {
>  	int i, counter;
>  	struct stat st;
> -	pid_t pid = 0;
>  	int flags;
>  	int err;
>  	unsigned long waking = 0;
> @@ -572,7 +571,7 @@ static int __cmd_record(int argc, const char **argv)
>  
>  	if (forks) {
>  		child_pid = fork();
> -		if (pid < 0) {
> +		if (child_pid < 0) {



Oops :)


Since I'm preparing some fixes for .35 in perf tools, I'm queuing this one
too.

Thanks.

Re: [PATCH] perf-record: Check correct pid when forking

[Borislav Petkov]

From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Mon, May 31, 2010 at 11:27:26PM +0200

Hi Frederic :),

> On Mon, May 31, 2010 at 11:18:18PM +0200, Borislav Petkov wrote:
> > When forking the child to be traced, we should check the correct return
> > value from fork() and not a local variable which is otherwise unused.
> > 
> > Signed-off-by: Borislav Petkov <bp@alien8.de>
> > ---
> >  tools/perf/builtin-record.c |    3 +--
> >  1 files changed, 1 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index 9bc8905..dc3435e 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -503,7 +503,6 @@ static int __cmd_record(int argc, const char **argv)
> >  {
> >  	int i, counter;
> >  	struct stat st;
> > -	pid_t pid = 0;
> >  	int flags;
> >  	int err;
> >  	unsigned long waking = 0;
> > @@ -572,7 +571,7 @@ static int __cmd_record(int argc, const char **argv)
> >  
> >  	if (forks) {
> >  		child_pid = fork();
> > -		if (pid < 0) {
> > +		if (child_pid < 0) {
> 
> 
> 
> Oops :)

Yeah, this looked really odd and I had recheck it couple of times just
to be sure I'm not missing any "hidden" semantics. And it seems that
nobody has hit that because obviously we always fork fine :)

-- 
Regards/Gruss,
    Boris.

[tip:perf/urgent] perf-record: Check correct pid when forking

[tip-bot for Borislav Petkov]

Commit-ID:  2fb750e825b5347de0390315f4284f13709a9856
Gitweb:     http://git.kernel.org/tip/2fb750e825b5347de0390315f4284f13709a9856
Author:     Borislav Petkov <bp@alien8.de>
AuthorDate: Mon, 31 May 2010 23:18:18 +0200
Committer:  Frederic Weisbecker <fweisbec@gmail.com>
CommitDate: Tue, 1 Jun 2010 00:57:14 +0200

perf-record: Check correct pid when forking

When forking the child to be traced, we should check the correct
return value from fork() and not a local variable which is otherwise
unused.

Signed-off-by: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <20100531211818.GA30175@liondog.tnic>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 tools/perf/builtin-record.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 9bc8905..dc3435e 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -503,7 +503,6 @@ static int __cmd_record(int argc, const char **argv)
 {
 	int i, counter;
 	struct stat st;
-	pid_t pid = 0;
 	int flags;
 	int err;
 	unsigned long waking = 0;
@@ -572,7 +571,7 @@ static int __cmd_record(int argc, const char **argv)
 
 	if (forks) {
 		child_pid = fork();
-		if (pid < 0) {
+		if (child_pid < 0) {
 			perror("failed to fork");
 			exit(-1);
 		}