audit: consistently record PIDs with task_tgid_nr()

Unfortunately we record PIDs in audit records using a variety of
methods despite the correct way being the use of task_tgid_nr().
This patch converts all of these callers, except for the case of
AUDIT_SET in audit_receive_msg() (see the comment in the code).

Reported-by: Jeff Vander Stoep <jeffv@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
diff --git a/security/lsm_audit.c b/security/lsm_audit.c
index cccbf30..45d927a 100644
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
@@ -220,7 +220,7 @@
 	 */
 	BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2);
 
-	audit_log_format(ab, " pid=%d comm=", task_pid_nr(current));
+	audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current));
 	audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm)));
 
 	switch (a->type) {
@@ -294,7 +294,7 @@
 	case LSM_AUDIT_DATA_TASK: {
 		struct task_struct *tsk = a->u.tsk;
 		if (tsk) {
-			pid_t pid = task_pid_nr(tsk);
+			pid_t pid = task_tgid_nr(tsk);
 			if (pid) {
 				char comm[sizeof(tsk->comm)];
 				audit_log_format(ab, " opid=%d ocomm=", pid);