* [PATCH] cgroup: fix attach task fail when subtree_control configured
@ 2022-04-08 10:23 zhaoyang.huang
2022-04-08 17:54 ` Tejun Heo
0 siblings, 1 reply; 2+ messages in thread
From: zhaoyang.huang @ 2022-04-08 10:23 UTC (permalink / raw)
To: Tejun Heo, Zefan Li, Johannes Weiner, Zhaoyang Huang,
linux-kernel, cgroups, ke.wang
From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
It is found that task attach to a vacant cgroup will fail when its
subtree_control has been configured. Fix it by judging if there is no chrildren
existed.
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
kernel/cgroup/cgroup.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 919194d..f00583b 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2561,6 +2561,9 @@ static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx)
*/
int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp)
{
+ struct cgroup_subsys_state *css = &dst_cgrp->self;
+ struct list_head *children = &css->children;
+
/* v1 doesn't have any restriction */
if (!cgroup_on_dfl(dst_cgrp))
return 0;
@@ -2581,7 +2584,7 @@ int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp)
return 0;
/* apply no-internal-process constraint */
- if (dst_cgrp->subtree_control)
+ if (dst_cgrp->subtree_control && !list_empty(children))
return -EBUSY;
return 0;
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] cgroup: fix attach task fail when subtree_control configured
2022-04-08 10:23 [PATCH] cgroup: fix attach task fail when subtree_control configured zhaoyang.huang
@ 2022-04-08 17:54 ` Tejun Heo
0 siblings, 0 replies; 2+ messages in thread
From: Tejun Heo @ 2022-04-08 17:54 UTC (permalink / raw)
To: zhaoyang.huang
Cc: Zefan Li, Johannes Weiner, Zhaoyang Huang, linux-kernel, cgroups,
ke.wang
On Fri, Apr 08, 2022 at 06:23:14PM +0800, zhaoyang.huang wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> It is found that task attach to a vacant cgroup will fail when its
> subtree_control has been configured. Fix it by judging if there is no chrildren
> existed.
>
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
If I'm not misunderstanding, that's the intended behavior. Can you please
take a look at Documentation/admin-guide/cgroup-v2.rst and confirm what
you're trying to do?
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 2+ messages in thread
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