1 files changed, 37 insertions, 15 deletions

diff --git a/sound/core/seq/seq_fifo.c b/sound/core/seq/seq_fifo.c
index 91cce1890111..81fa4320ddf6 100644
--- a/sound/core/seq/seq_fifo.c
+++ b/sound/core/seq/seq_fifo.c
@@ -101,13 +101,17 @@ int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
 			  struct snd_seq_event *event)
 {
 	struct snd_seq_event_cell *cell;
+	struct snd_seq_pool *pool;
+	bool linked;
 	int err;
 
 	if (snd_BUG_ON(!f))
 		return -EINVAL;
 
 	guard(snd_seq_fifo)(f);
-	err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL, NULL); /* always non-blocking */
+retry:
+	pool = READ_ONCE(f->pool);
+	err = snd_seq_event_dup(pool, event, &cell, 1, NULL, NULL); /* always non-blocking */
 	if (err < 0) {
 		if ((err == -ENOMEM) || (err == -EAGAIN))
 			atomic_inc(&f->overflow);
@@ -115,14 +119,24 @@ int snd_seq_fifo_event_in(struct snd_seq_fifo *f,
 	}
 		
 	/* append new cells to fifo */
+	linked = false;
 	scoped_guard(spinlock_irqsave, &f->lock) {
-		if (f->tail != NULL)
-			f->tail->next = cell;
-		f->tail = cell;
-		if (f->head == NULL)
-			f->head = cell;
-		cell->next = NULL;
-		f->cells++;
+		if (cell->pool == f->pool) {
+			if (f->tail)
+				f->tail->next = cell;
+			f->tail = cell;
+			if (!f->head)
+				f->head = cell;
+			cell->next = NULL;
+			f->cells++;
+			linked = true;
+		}
+	}
+
+	if (!linked) {
+		/* Retry against the replacement pool after resize publishes it. */
+		snd_seq_cell_free(cell);
+		goto retry;
 	}
 
 	/* wakeup client */
@@ -194,13 +208,21 @@ int snd_seq_fifo_cell_out(struct snd_seq_fifo *f,
 void snd_seq_fifo_cell_putback(struct snd_seq_fifo *f,
 			       struct snd_seq_event_cell *cell)
 {
+	bool linked = false;
+
 	if (cell) {
-		guard(spinlock_irqsave)(&f->lock);
-		cell->next = f->head;
-		f->head = cell;
-		if (!f->tail)
-			f->tail = cell;
-		f->cells++;
+		scoped_guard(spinlock_irqsave, &f->lock) {
+			if (cell->pool == f->pool) {
+				cell->next = f->head;
+				f->head = cell;
+				if (!f->tail)
+					f->tail = cell;
+				f->cells++;
+				linked = true;
+			}
+		}
+		if (!linked)
+			snd_seq_cell_free(cell);
 	}
 }
 
@@ -237,7 +259,7 @@ int snd_seq_fifo_resize(struct snd_seq_fifo *f, int poolsize)
 		oldpool = f->pool;
 		oldhead = f->head;
 		/* exchange pools */
-		f->pool = newpool;
+		WRITE_ONCE(f->pool, newpool);
 		f->head = NULL;
 		f->tail = NULL;
 		f->cells = 0;