dlm: memory leaks on error path in dlm_user_request()

BugLink: https://bugs.launchpad.net/bugs/1811647

commit d47b41ac upstream.

According to comment in dlm_user_request() ua should be freed
in dlm_free_lkb() after successful attach to lkb.

However ua is attached to lkb not in set_lock_args() but later,
inside request_lock().

Fixes 597d0cae ("[DLM] dlm: user locks")
Cc: stable@kernel.org # 2.6.19
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

fs/dlm/lock.c

@@ -5795,20 +5795,20 @@ int dlm_user_request(struct dlm_ls *ls, struct dlm_user_args *ua,
 			goto out;
 		}
 	}
-
-	/* After ua is attached to lkb it will be freed by dlm_free_lkb().
-	   When DLM_IFL_USER is set, the dlm knows that this is a userspace
-	   lock and that lkb_astparam is the dlm_user_args structure. */
-
 	error = set_lock_args(mode, &ua->lksb, flags, namelen, timeout_cs,
 			      fake_astfn, ua, fake_bastfn, &args);
-	lkb->lkb_flags |= DLM_IFL_USER;
-
 	if (error) {
+		kfree(ua->lksb.sb_lvbptr);
+		ua->lksb.sb_lvbptr = NULL;
+		kfree(ua);
 		__put_lkb(ls, lkb);
 		goto out;
 	}
 
+	/* After ua is attached to lkb it will be freed by dlm_free_lkb().
+	   When DLM_IFL_USER is set, the dlm knows that this is a userspace
+	   lock and that lkb_astparam is the dlm_user_args structure. */
+	lkb->lkb_flags |= DLM_IFL_USER;
 	error = request_lock(ls, lkb, name, namelen, &args);
 
 	switch (error) {