[PATCH 5.4 016/149] ALSA: usx2y: Dont call free_pages_exact() with NULL address

Greg Kroah-Hartman
2021-07-19T16:42:58Z

From: Takashi Iwai <tiwai@suse.de>

[ 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>
---
sound/usb/usx2y/usb_stream.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sound/usb/usx2y/usb_stream.c b/sound/usb/usx2y/usb_stream.c
index 091c071b270a..cff684942c4f 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;
}
--
2.30.2