We have single pids cgroup hierarchy which is shared among all VEs.
So when we start several VEs, cgroup_add_ve_root_files() will be called
more than once for the single pids cgroup, leading to:
"cgroup_add_ve_root_files: failed to add cgroup.subgroups_limit, err=-17"
This may seem as harmless message at first, but it is not because
cgroup_add_file()
doesn't handle error properly:
cfe = kzalloc(sizeof(*cfe), GFP_KERNEL);
....
dentry->d_fsdata = cfe;
....
error = cgroup_create_file(dentry, mode | S_IFREG, cgrp->root->sb);
if (!error) {
list_add_tail(&cfe->node, &parent->files);
cfe = NULL;
}
....
kfree(cfe);
return error;
As one can see above we leave freed cfe in dentry if cgroup_create_file() fails.
So let's make sure that we call cgroup_add_ve_root_files() only once per
cgroup to avoid that problem and message in dmesg as well.
https://jira.sw.ru/browse/PSBM-59693
Signed-off-by: Andrey Ryabinin <aryabi...@virtuozzo.com>
---
kernel/cgroup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3e2de0b4..e8ec5f2 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4271,8 +4271,8 @@ void cgroup_mark_ve_root(struct ve_struct *ve)
mutex_lock(&cgroup_mutex);
for_each_active_root(root) {
cgrp = task_cgroup_from_root(ve->init_task, root);
- set_bit(CGRP_VE_ROOT, &cgrp->flags);
- cgroup_add_ve_root_files(cgrp, NULL, files);
+ if (!test_and_set_bit(CGRP_VE_ROOT, &cgrp->flags))
+ cgroup_add_ve_root_files(cgrp, NULL, files);
}
mutex_unlock(&cgroup_mutex);
}
--
2.10.2
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