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SubjectRe: [PATCH 1/2] cgroups: Fix to return errno in a failure path
Quoting Li Zefan (lizf@cn.fujitsu.com):
> In cgroup_create(), if alloc_css_id() returns failure, the errno
> is not propagated to userspace, so mkdir will fail silently.
>
> To trigger this bug, we mount blkio (or memory subsystem), and
> create more then 65534 cgroups. (The number of cgroups is limited
> to 65535 if a subsystem has use_id == 1)
>
> # mount -t cgroup -o blkio xxx /mnt
> # for ((i = 0; i < 65534; i++)); do mkdir /mnt/$i; done
> # mkdir /mnt/65534
> (should return ENOSPC)
> #
>
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

Yup.

Acked-by: Serge Hallyn <serue@us.ibm.com>

> ---
> cgroup.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> --- a/kernel/cgroup.c.orig 2010-01-19 16:37:37.000000000 +0800
> +++ a/kernel/cgroup.c 2010-01-19 16:39:07.000000000 +0800
> @@ -3279,14 +3279,17 @@ static long cgroup_create(struct cgroup
>
> for_each_subsys(root, ss) {
> struct cgroup_subsys_state *css = ss->create(ss, cgrp);
> +
> if (IS_ERR(css)) {
> err = PTR_ERR(css);
> goto err_destroy;
> }
> init_cgroup_css(css, ss, cgrp);
> - if (ss->use_id)
> - if (alloc_css_id(ss, parent, cgrp))
> + if (ss->use_id) {
> + err = alloc_css_id(ss, parent, cgrp);
> + if (err)
> goto err_destroy;
> + }
> /* At error, ->destroy() callback has to free assigned ID. */
> }
>
> _______________________________________________
> Containers mailing list
> Containers@lists.linux-foundation.org
> https://lists.linux-foundation.org/mailman/listinfo/containers


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