[PATCH] ceph: Fix uninitialized dentry pointer in ceph_real_mount()

From: Geert Uytterhoeven
Date: Thu Oct 13 2016 - 11:17:00 EST


fs/ceph/super.c: In function âceph_real_mountâ:
fs/ceph/super.c:818: warning: ârootâ may be used uninitialized in this function

If s_root is already valid, dentry pointer root is never initialized,
and returned by ceph_real_mount(). This will cause a crash later when
the caller dereferences the pointer.

Fix this by initializing root early.

Fixes: ce2728aaa82bbeba ("ceph: avoid accessing / when mounting a subpath")
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
Compile-tested only.
---
fs/ceph/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index a29ffce981879d5f..794c5fd0e0cf5e45 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -821,7 +821,8 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
dout("mount start %p\n", fsc);
mutex_lock(&fsc->client->mount_mutex);

- if (!fsc->sb->s_root) {
+ root = fsc->sb->s_root;
+ if (!root) {
const char *path;
err = __ceph_open_session(fsc->client, started);
if (err < 0)
--
1.9.1