From: Takashi Iwai <tiwai@suse.de>
Date: Mon, 17 May 2021 13:15:43 +0000 (+0200)
Subject: ALSA: usx2y: Don't call free_pages_exact() with NULL address
X-Git-Tag: v5.12.19~239
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bee295f5e03510252d18b25cc1d26230256eb87a;p=thirdparty%2Fkernel%2Fstable.git

ALSA: usx2y: Don't call free_pages_exact() with NULL address

[ Upstream commit cae0cf651adccee2c3f376e78f30fbd788d0829f ]

Unlike some other functions, we can't pass NULL pointer to
free_pages_exact().  Add a proper NULL check for avoiding possible
Oops.

Link: https://lore.kernel.org/r/20210517131545.27252-10-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/sound/usb/usx2y/usb_stream.c b/sound/usb/usx2y/usb_stream.c
index 091c071b270af..cff684942c4f0 100644
--- a/sound/usb/usx2y/usb_stream.c
+++ b/sound/usb/usx2y/usb_stream.c
@@ -142,8 +142,11 @@ void usb_stream_free(struct usb_stream_kernel *sk)
 	if (!s)
 		return;
 
-	free_pages_exact(sk->write_page, s->write_size);
-	sk->write_page = NULL;
+	if (sk->write_page) {
+		free_pages_exact(sk->write_page, s->write_size);
+		sk->write_page = NULL;
+	}
+
 	free_pages_exact(s, s->read_size);
 	sk->s = NULL;
 }