9p: check memory allocation result for cachetag

Check memory allocation result for cachetag in mount option parsing and
fix potential memory leak in the error case.

Link: http://lkml.kernel.org/r/1521614889-73446-1-git-send-email-cgxu519@gmx.com
Signed-off-by: Chengguang Xu <cgxu519@gmx.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: <v9fs-developer@lists.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index 8fb89ddc6cc7ec3be59236cd5e493ffcc44719ae..e622f0f10502886556d637b2c5951efce78fcba0 100644 (file)
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -292,6 +292,10 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 #ifdef CONFIG_9P_FSCACHE
                        kfree(v9ses->cachetag);
                        v9ses->cachetag = match_strdup(&args[0]);
+                       if (!v9ses->cachetag) {
+                               ret = -ENOMEM;
+                               goto free_and_return;
+                       }
 #endif
                        break;
                case Opt_cache:
@@ -471,6 +475,9 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
        return fid;
 
 err_clnt:
+#ifdef CONFIG_9P_FSCACHE
+       kfree(v9ses->cachetag);
+#endif
        p9_client_destroy(v9ses->clnt);
 err_names:
        kfree(v9ses->uname);