[PATCH -tip] Documentation/accounting/getdelays.c intialize the variable before using it

[PATCH -tip] Documentation/accounting/getdelays.c intialize the variable before using it

[Jaswinder Singh Rajput]

May be in some cases cmd_type will be used uninitialized.

Also fixes compilation warning:

   CC [M]  Documentation/DocBook/procfs_example.o
  Documentation/accounting/getdelays.c: In function ‘main’:
  Documentation/accounting/getdelays.c:249: warning: ‘cmd_type’ may be used uninitialized in this function

Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
---
 Documentation/accounting/getdelays.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index 7ea2311..36aae3b 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -246,7 +246,7 @@ void print_ioacct(struct taskstats *t)
 
 int main(int argc, char *argv[])
 {
-	int c, rc, rep_len, aggr_len, len2, cmd_type;
+	int c, rc, rep_len, aggr_len, len2, cmd_type = TASKSTATS_CMD_ATTR_UNSPEC;
 	__u16 id;
 	__u32 mypid;
 
-- 
1.6.1.1

Re: [PATCH -tip] Documentation/accounting/getdelays.c intialize the variable before using it

[Andrew Morton]

On Wed, 20 May 2009 10:44:44 +0530 Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:

> 
> May be in some cases cmd_type will be used uninitialized.
> 
> Also fixes compilation warning:
> 
>    CC [M]  Documentation/DocBook/procfs_example.o
>   Documentation/accounting/getdelays.c: In function ___main___:
>   Documentation/accounting/getdelays.c:249: warning: ___cmd_type___ may be used uninitialized in this function
> 
> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
> ---
>  Documentation/accounting/getdelays.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
> index 7ea2311..36aae3b 100644
> --- a/Documentation/accounting/getdelays.c
> +++ b/Documentation/accounting/getdelays.c
> @@ -246,7 +246,7 @@ void print_ioacct(struct taskstats *t)
>  
>  int main(int argc, char *argv[])
>  {
> -	int c, rc, rep_len, aggr_len, len2, cmd_type;
> +	int c, rc, rep_len, aggr_len, len2, cmd_type = TASKSTATS_CMD_ATTR_UNSPEC;
>  	__u16 id;
>  	__u32 mypid;
>  

>From my reading of the code there is no bug here - we'll only use
cmd_type if tid != 0, and cmd_type is always initialised when tid != 0.

But I suppose we should squish the warning anyway.

btw, whichever version of gcc you're using has apparently regressed -
my gcc-4.3.0 manages to work out what's happening.  Hence please prefer
to include the gcc version in the changelog.  And send a bug report at
the gcc guys if appropriate ;)

Re: [PATCH -tip] Documentation/accounting/getdelays.c intialize the variable before using it

[Jaswinder Singh Rajput]

On Tue, 2009-05-26 at 23:54 -0700, Andrew Morton wrote:
> On Wed, 20 May 2009 10:44:44 +0530 Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> 
> > 
> > May be in some cases cmd_type will be used uninitialized.
> > 
> > Also fixes compilation warning:
> > 
> >    CC [M]  Documentation/DocBook/procfs_example.o
> >   Documentation/accounting/getdelays.c: In function ___main___:
> >   Documentation/accounting/getdelays.c:249: warning: ___cmd_type___ may be used uninitialized in this function
> > 
> > Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
> > ---
> >  Documentation/accounting/getdelays.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
> > index 7ea2311..36aae3b 100644
> > --- a/Documentation/accounting/getdelays.c
> > +++ b/Documentation/accounting/getdelays.c
> > @@ -246,7 +246,7 @@ void print_ioacct(struct taskstats *t)
> >  
> >  int main(int argc, char *argv[])
> >  {
> > -	int c, rc, rep_len, aggr_len, len2, cmd_type;
> > +	int c, rc, rep_len, aggr_len, len2, cmd_type = TASKSTATS_CMD_ATTR_UNSPEC;
> >  	__u16 id;
> >  	__u32 mypid;
> >  
> 
> >From my reading of the code there is no bug here - we'll only use
> cmd_type if tid != 0, and cmd_type is always initialised when tid != 0.
> 
> But I suppose we should squish the warning anyway.
> 
> btw, whichever version of gcc you're using has apparently regressed -
> my gcc-4.3.0 manages to work out what's happening.  Hence please prefer
> to include the gcc version in the changelog.  And send a bug report at
> the gcc guys if appropriate ;)

my gcc version is 4.3.2 20081105 (Red Hat 4.3.2-7) (GCC)

But I heard from jejb that 4.3.3 fixed some of these warnings.

Thanks,
--
JSR

Re: [PATCH -tip] Documentation/accounting/getdelays.c intialize the variable before using it

[Balbir Singh]

* Jaswinder Singh Rajput <jaswinder@kernel.org> [2009-05-20 10:44:44]:

> 
> May be in some cases cmd_type will be used uninitialized.
> 
> Also fixes compilation warning:
> 
>    CC [M]  Documentation/DocBook/procfs_example.o
>   Documentation/accounting/getdelays.c: In function ???main???:
>   Documentation/accounting/getdelays.c:249: warning: ???cmd_type??? may be used uninitialized in this function
> 
> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
> ---
>  Documentation/accounting/getdelays.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
> index 7ea2311..36aae3b 100644
> --- a/Documentation/accounting/getdelays.c
> +++ b/Documentation/accounting/getdelays.c
> @@ -246,7 +246,7 @@ void print_ioacct(struct taskstats *t)
> 
>  int main(int argc, char *argv[])
>  {
> -	int c, rc, rep_len, aggr_len, len2, cmd_type;
> +	int c, rc, rep_len, aggr_len, len2, cmd_type = TASKSTATS_CMD_ATTR_UNSPEC;

Thanks. The fix seems correct


Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>

I am away traveling with almost no time to check emails, hence I've
been slow responding. Thanks for being patient. 

-- 
	Balbir