* [PATCH] cgroup: use uninitialized_var() for may-be uninitialized variable
@ 2014-04-22 5:44 Jianyu Zhan
2014-04-22 6:26 ` Li Zefan
0 siblings, 1 reply; 3+ messages in thread
From: Jianyu Zhan @ 2014-04-22 5:44 UTC (permalink / raw)
To: tj, lizefan; +Cc: containers, cgroups, linux-kernel, nasa4836
To suppress this warning:
warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
int err;
^
Use the uninitialized_var() to decalre err. It also serves to be good documetation.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
---
kernel/cgroup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 24675f5..930569c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4144,7 +4144,7 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
{
struct cgroup *parent = cgrp->parent;
struct cgroup_subsys_state *css;
- int err;
+ int uninitialized_var(err);
lockdep_assert_held(&cgroup_mutex);
--
2.0.0-rc0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] cgroup: use uninitialized_var() for may-be uninitialized variable
2014-04-22 5:44 [PATCH] cgroup: use uninitialized_var() for may-be uninitialized variable Jianyu Zhan
@ 2014-04-22 6:26 ` Li Zefan
2014-04-22 7:52 ` Jianyu Zhan
0 siblings, 1 reply; 3+ messages in thread
From: Li Zefan @ 2014-04-22 6:26 UTC (permalink / raw)
To: Jianyu Zhan; +Cc: tj, containers, cgroups, linux-kernel
On 2014/4/22 13:44, Jianyu Zhan wrote:
> To suppress this warning:
>
> warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
> int err;
> ^
I don't see this warning, and I don't see how this is possible.
static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
{
struct cgroup *parent = cgrp->parent;
struct cgroup_subsys_state *css;
int err;
lockdep_assert_held(&cgroup_mutex);
css = ss->css_alloc(cgroup_css(parent, ss));
if (IS_ERR(css))
return PTR_ERR(css);
err = percpu_ref_init(&css->refcnt, css_release);
if (err)
goto err_free_css;
...
return err;
}
>
> Use the uninitialized_var() to decalre err. It also serves to be good documetation.
>
anyway, uninitialized_var() should be avoided if possible.
nack
> Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
> ---
> kernel/cgroup.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 24675f5..930569c 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -4144,7 +4144,7 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss)
> {
> struct cgroup *parent = cgrp->parent;
> struct cgroup_subsys_state *css;
> - int err;
> + int uninitialized_var(err);
>
> lockdep_assert_held(&cgroup_mutex);
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] cgroup: use uninitialized_var() for may-be uninitialized variable
2014-04-22 6:26 ` Li Zefan
@ 2014-04-22 7:52 ` Jianyu Zhan
0 siblings, 0 replies; 3+ messages in thread
From: Jianyu Zhan @ 2014-04-22 7:52 UTC (permalink / raw)
To: Li Zefan; +Cc: Tejun Heo, containers, Cgroups, LKML
Hi, Li,
On Tue, Apr 22, 2014 at 2:26 PM, Li Zefan <lizefan@huawei.com> wrote:
>
> I don't see this warning, and I don't see how this is possible.
You are right. No such warning.
It is triggered by the other patch, should be fixed in that patch.
Thanks,
Jianyu Zhan
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-04-22 7:53 UTC | newest]
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2014-04-22 5:44 [PATCH] cgroup: use uninitialized_var() for may-be uninitialized variable Jianyu Zhan
2014-04-22 6:26 ` Li Zefan
2014-04-22 7:52 ` Jianyu Zhan
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