1 files changed, 37 insertions, 18 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 60c737e423a1..6fe29715105b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -618,20 +618,18 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
 }
 
 /*
- * Dequeue a signal and return the element to the caller, which is
- * expected to free it.
- *
- * All callers have to hold the siglock.
+ * Try to dequeue a signal. If a deliverable signal is found fill in the
+ * caller provided siginfo and return the signal number. Otherwise return
+ * 0.
  */
-int dequeue_signal(struct task_struct *tsk, sigset_t *mask,
-		   kernel_siginfo_t *info, enum pid_type *type)
+int dequeue_signal(sigset_t *mask, kernel_siginfo_t *info, enum pid_type *type)
 {
+	struct task_struct *tsk = current;
 	bool resched_timer = false;
 	int signr;
 
-	/* We only dequeue private signals from ourselves, we don't let
-	 * signalfd steal them
-	 */
+	lockdep_assert_held(&tsk->sighand->siglock);
+
 	*type = PIDTYPE_PID;
 	signr = __dequeue_signal(&tsk->pending, mask, info, &resched_timer);
 	if (!signr) {
@@ -1940,10 +1938,11 @@ struct sigqueue *sigqueue_alloc(void)
 
 void sigqueue_free(struct sigqueue *q)
 {
-	unsigned long flags;
 	spinlock_t *lock = &current->sighand->siglock;
+	unsigned long flags;
 
-	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+	if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
+		return;
 	/*
 	 * We must hold ->siglock while testing q->list
 	 * to serialize with collect_signal() or with
@@ -1971,7 +1970,10 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
 	unsigned long flags;
 	int ret, result;
 
-	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
+	if (WARN_ON_ONCE(!(q->flags & SIGQUEUE_PREALLOC)))
+		return 0;
+	if (WARN_ON_ONCE(q->info.si_code != SI_TIMER))
+		return 0;
 
 	ret = -1;
 	rcu_read_lock();
@@ -2006,7 +2008,6 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
 		 * If an SI_TIMER entry is already queue just increment
 		 * the overrun count.
 		 */
-		BUG_ON(q->info.si_code != SI_TIMER);
 		q->info.si_overrun++;
 		result = TRACE_SIGNAL_ALREADY_PENDING;
 		goto out;
@@ -2793,8 +2794,7 @@ relock:
 		type = PIDTYPE_PID;
 		signr = dequeue_synchronous_signal(&ksig->info);
 		if (!signr)
-			signr = dequeue_signal(current, &current->blocked,
-					       &ksig->info, &type);
+			signr = dequeue_signal(&current->blocked, &ksig->info, &type);
 
 		if (!signr)
 			break; /* will return 0 */
@@ -2888,6 +2888,8 @@ relock:
 		current->flags |= PF_SIGNALED;
 
 		if (sig_kernel_coredump(signr)) {
+			int ret;
+
 			if (print_fatal_signals)
 				print_fatal_signal(signr);
 			proc_coredump_connector(current);
@@ -2899,7 +2901,24 @@ relock:
 			 * first and our do_group_exit call below will use
 			 * that value and ignore the one we pass it.
 			 */
-			do_coredump(&ksig->info);
+			ret = do_coredump(&ksig->info);
+			if (ret)
+				coredump_report_failure("coredump has not been created, error %d",
+					ret);
+			else if (!IS_ENABLED(CONFIG_COREDUMP)) {
+				/*
+				 * Coredumps are not available, can't fail collecting
+				 * the coredump.
+				 *
+				 * Leave a note though that the coredump is going to be
+				 * not created. This is not an error or a warning as disabling
+				 * support in the kernel for coredumps isn't commonplace, and
+				 * the user must've built the kernel with the custom config so
+				 * let them know all works as desired.
+				 */
+				coredump_report("no coredump collected as "
+					"that is disabled in the kernel configuration");
+			}
 		}
 
 		/*
@@ -3648,7 +3667,7 @@ static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
 	signotset(&mask);
 
 	spin_lock_irq(&tsk->sighand->siglock);
-	sig = dequeue_signal(tsk, &mask, info, &type);
+	sig = dequeue_signal(&mask, info, &type);
 	if (!sig && timeout) {
 		/*
 		 * None ready, temporarily unblock those we're interested
@@ -3667,7 +3686,7 @@ static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
 		spin_lock_irq(&tsk->sighand->siglock);
 		__set_task_blocked(tsk, &tsk->real_blocked);
 		sigemptyset(&tsk->real_blocked);
-		sig = dequeue_signal(tsk, &mask, info, &type);
+		sig = dequeue_signal(&mask, info, &type);
 	}
 	spin_unlock_irq(&tsk->sighand->siglock);