From e99ed4de1731f79868b00a7ff9f479a55a4799a7 Mon Sep 17 00:00:00 2001 From: Serge Hallyn Date: Sun, 17 Apr 2016 15:04:31 -0500 Subject: [PATCH] kernfs_path_from_node_locked: don't overwrite nlen We've calculated @len to be the bytes we need for '/..' entries from @kn_from to the common ancestor, and calculated @nlen to be the extra bytes we need to get from the common ancestor to @kn_to. We use them as such at the end. But in the loop copying the actual entries, we overwrite @nlen. Use a temporary variable for that instead. Without this, the return length, when the buffer is large enough, is wrong. (When the buffer is NULL or too small, the returned value is correct. The buffer contents are also correct.) Interestingly, no callers of this function are affected by this as of yet. However the upcoming cgroup_show_path() will be. Signed-off-by: Serge Hallyn --- fs/kernfs/dir.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 03b688d19f69..37f9678ae4df 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -153,9 +153,9 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, p = buf + len + nlen; *p = '\0'; for (kn = kn_to; kn != common; kn = kn->parent) { - nlen = strlen(kn->name); - p -= nlen; - memcpy(p, kn->name, nlen); + size_t tmp = strlen(kn->name); + p -= tmp; + memcpy(p, kn->name, tmp); *(--p) = '/'; } -- 2.20.1