Re: linux-next: build warning in Linus' tree

[Herbert Xu]

On Wed, May 26, 2010 at 11:43:06AM +1000, Stephen Rothwell wrote:
> Hi Dave,
> 
> Today's linux-next build (x86_64 allmodconfig) produced this warning:
> 
> net/core/sock.c: In function 'sock_update_classid':
> include/net/cls_cgroup.h:42: warning: 'classid' may be used uninitialized in this function
> include/net/cls_cgroup.h:42: note: 'classid' was declared here
> 
> In the case that rcu_dereference() returns a value < 0, classid will not
> be assigned in task_cls_classid().  I don't know if this is possible - if
> not, then why is the test there?

This is a genuine bug.  I don't know why my gcc didn't warn about
it.

cls_cgroup: Initialise classid when module is absent

When the cls_cgroup module is not loaded, task_cls_classid will
return an uninitialised classid instead of zero.

Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

diff --git a/include/net/cls_cgroup.h b/include/net/cls_cgroup.h
index 6cf4486..726cc35 100644
--- a/include/net/cls_cgroup.h
+++ b/include/net/cls_cgroup.h
@@ -39,7 +39,7 @@ extern int net_cls_subsys_id;
 static inline u32 task_cls_classid(struct task_struct *p)
 {
 	int id;
-	u32 classid;
+	u32 classid = 0;
 
 	if (in_interrupt())
 		return 0;

Thanks,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/