[PATCH 01/11] signal: Compute the exit_code in get_signal

["Eric W. Biederman" <ebiederm@xmission.com>]

Update get_signal so it calls do_group_exit with the correct
exit_code.

Make the default exit_code 0, so that the special case for threads
killed by de_thread falls out naturally.

Update do_group_exit to trust the exit_code passed in except when
SIGNAL_GROUP_EXIT is set.

Moving the computation of exit_code into get_signal makes other
cleanups possible.
---
 kernel/exit.c   |  4 ++--
 kernel/signal.c | 12 ++++++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index f50d73c272d6..ae143be7c831 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1098,7 +1098,7 @@ do_group_exit(int exit_code)
 	if (sig->flags & SIGNAL_GROUP_EXIT)
 		exit_code = sig->group_exit_code;
 	else if (sig->group_exec_task)
-		exit_code = 0;
+		;
 	else {
 		struct sighand_struct *const sighand = current->sighand;
 
@@ -1107,7 +1107,7 @@ do_group_exit(int exit_code)
 			/* Another thread got here before we took the lock.  */
 			exit_code = sig->group_exit_code;
 		else if (sig->group_exec_task)
-			exit_code = 0;
+			;
 		else {
 			sig->group_exit_code = exit_code;
 			sig->flags = SIGNAL_GROUP_EXIT;
diff --git a/kernel/signal.c b/kernel/signal.c
index 9c2b32c4d755..39fbf9c9474a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2865,10 +2865,13 @@ bool get_signal(struct ksignal *ksig)
 	for (;;) {
 		struct k_sigaction *ka;
 		enum pid_type type;
+		int exit_code = 0;
 
 		/* Has this task already been marked for death? */
 		if ((signal->flags & SIGNAL_GROUP_EXIT) ||
 		     signal->group_exec_task) {
+			if (signal->flags & SIGNAL_GROUP_EXIT)
+				exit_code = signal->group_exit_code;
 			signr = SIGKILL;
 			sigdelset(&current->pending.signal, SIGKILL);
 			trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
@@ -2998,14 +3001,15 @@ bool get_signal(struct ksignal *ksig)
 			continue;
 		}
 
+		/*
+		 * Anything else is fatal, maybe with a core dump.
+		 */
+		exit_code = signr;
 	fatal:
 		spin_unlock_irq(&sighand->siglock);
 		if (unlikely(cgroup_task_frozen(current)))
 			cgroup_leave_frozen(true);
 
-		/*
-		 * Anything else is fatal, maybe with a core dump.
-		 */
 		current->flags |= PF_SIGNALED;
 
 		if (sig_kernel_coredump(signr)) {
@@ -3035,7 +3039,7 @@ bool get_signal(struct ksignal *ksig)
 		/*
 		 * Death signals, no core dump.
 		 */
-		do_group_exit(signr);
+		do_group_exit(exit_code);
 		/* NOTREACHED */
 	}
 	spin_unlock_irq(&sighand->siglock);
-- 
2.41.0