cgroup: make cgroup_path() not print double slashes (da1f296f) · Commits · 戴 / test

While reimplementing cgroup_path(), ("cgroup: fix cgroup_path() vs rename() race") introduced a bug where the path of a non-root cgroup would have two slahses at the beginning, which is caused by treating the root cgroup which has the name '/' like non-root cgroups. $ grep systemd /proc/self/cgroup 1:name=systemd://user/root/1 Fix it by special casing root cgroup case and not looping over it in the normal path. Signed-off-by:

Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com>

kernel/cgroup.c

+8 −5

Original line number	Diff line number	Diff line
		@@ -1811,11 +1811,17 @@ int cgroup_path(const struct cgroup cgrp, char buf, int buflen)
		int ret = -ENAMETOOLONG;
		char *start;

		if (!cgrp->parent) {
		if (strlcpy(buf, "/", buflen) >= buflen)
		return -ENAMETOOLONG;
		return 0;
		}

		start = buf + buflen - 1;
		*start = '\0';

		rcu_read_lock();
		while (cgrp) {
		do {
		const char *name = cgroup_name(cgrp);
		int len;

		@@ -1824,15 +1830,12 @@ int cgroup_path(const struct cgroup cgrp, char buf, int buflen)
		goto out;
		memcpy(start, name, len);

		if (!cgrp->parent)
		break;

		if (--start < buf)
		goto out;
		*start = '/';

		cgrp = cgrp->parent;
		}
		} while (cgrp->parent);
		ret = 0;
		memmove(buf, start, buf + buflen - start);
		out:

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