[PATCH v1 1/3] Revert "cgroup: enable cgroup_get_from_file() on cgroup1"

[Yosry Ahmed]

This reverts commit f3a2aebdd6fb90e444d595e46de64e822af419da.

Some callers of this function depended on the fact that it only supports
cgroup v2. Revert it now, and introduce a new function in a later patch
that supports both cgroup v1 and v2, for callers that need to support
both.

Reported-by: Christian A. Ehrhardt <lk@xxxxxxx>
Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
---
 kernel/cgroup/cgroup.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 764bdd5fd8d1..72e97422e9d9 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6218,6 +6218,11 @@ static struct cgroup *cgroup_get_from_file(struct file *f)
 		return ERR_CAST(css);
 
 	cgrp = css->cgroup;
+	if (!cgroup_on_dfl(cgrp)) {
+		cgroup_put(cgrp);
+		return ERR_PTR(-EBADF);
+	}
+
 	return cgrp;
 }
 
-- 
2.38.0.rc1.362.ged0d419d3c-goog