From da1f296fd2bfd5ad3c53d72a1ece593e821cf374 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Sun, 14 Apr 2013 10:32:19 -0700 Subject: [PATCH] cgroup: make cgroup_path() not print double slashes While reimplementing cgroup_path(), 65dff759d2 ("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 Cc: Li Zefan --- kernel/cgroup.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 678a22c..faf55f5 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -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: -- 2.7.4