* [PATCH] cgroup: fix potential null pointer risk
@ 2022-05-17 7:31 Shida Zhang
2022-05-17 17:07 ` Tejun Heo
0 siblings, 1 reply; 3+ messages in thread
From: Shida Zhang @ 2022-05-17 7:31 UTC (permalink / raw)
To: tj, lizefan.x, hannes; +Cc: zhangshida, starzhangzsd, linux-kernel, cgroups
We previously assumed 'parent' could be null,
so null pointer judgment should be added.
Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
---
kernel/cgroup/cgroup.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index adb820e98f24..7f230b0ab644 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5701,7 +5701,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
}
spin_unlock_irq(&css_set_lock);
- cgroup1_check_for_release(parent);
+ if (parent)
+ cgroup1_check_for_release(parent);
cgroup_bpf_offline(cgrp);
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] cgroup: fix potential null pointer risk
2022-05-17 7:31 [PATCH] cgroup: fix potential null pointer risk Shida Zhang
@ 2022-05-17 17:07 ` Tejun Heo
2022-05-18 1:04 ` Stephen Zhang
0 siblings, 1 reply; 3+ messages in thread
From: Tejun Heo @ 2022-05-17 17:07 UTC (permalink / raw)
To: Shida Zhang; +Cc: lizefan.x, hannes, zhangshida, linux-kernel, cgroups
On Tue, May 17, 2022 at 03:31:06PM +0800, Shida Zhang wrote:
> We previously assumed 'parent' could be null,
> so null pointer judgment should be added.
>
> Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
> ---
> kernel/cgroup/cgroup.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index adb820e98f24..7f230b0ab644 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -5701,7 +5701,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
> }
> spin_unlock_irq(&css_set_lock);
>
> - cgroup1_check_for_release(parent);
> + if (parent)
> + cgroup1_check_for_release(parent);
The function is never called for a root cgroup. The parent check up above in
the same function is superflous. So, maybe remove that?
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] cgroup: fix potential null pointer risk
2022-05-17 17:07 ` Tejun Heo
@ 2022-05-18 1:04 ` Stephen Zhang
0 siblings, 0 replies; 3+ messages in thread
From: Stephen Zhang @ 2022-05-18 1:04 UTC (permalink / raw)
To: Tejun Heo; +Cc: lizefan.x, hannes, zhangshida, linux-kernel, cgroups
Tejun Heo <tj@kernel.org> 于2022年5月18日周三 01:07写道：
>
> The function is never called for a root cgroup. The parent check up above in
> the same function is superflous. So, maybe remove that?
>
> Thanks.
>
> --
> tejun
Thanks. I will remake a patch based on this.
--
Stephen
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-05-18 1:04 UTC | newest]
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2022-05-17 7:31 [PATCH] cgroup: fix potential null pointer risk Shida Zhang
2022-05-17 17:07 ` Tejun Heo
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