[PATCH] ALSA: usb-audio: Fix possible NULL pointer dereference in snd_usb_pcm_has_fixed_rate()

[Jaroslav Kysela]

The subs function argument may be NULL, so do not use it before the NULL check.

Fixes: 291e9da91403 ("ALSA: usb-audio: Always initialize fixed_rate in snd_usb_find_implicit_fb_sync_format()")
Reported-by: coverity-bot <keescook at chromium.org>
Link: https://lore.kernel.org/alsa-devel/202301121424.4A79A485@keescook/
Signed-off-by: Jaroslav Kysela <perex at perex.cz>
---
 sound/usb/pcm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 1f72960d0d53..d959da7a1afb 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -160,11 +160,12 @@ find_substream_format(struct snd_usb_substream *subs,
 bool snd_usb_pcm_has_fixed_rate(struct snd_usb_substream *subs)
 {
 	const struct audioformat *fp;
-	struct snd_usb_audio *chip = subs->stream->chip;
+	struct snd_usb_audio *chip;
 	int rate = -1;
 
 	if (!subs)
 		return false;
+	chip = subs->stream->chip;
 	if (!(chip->quirk_flags & QUIRK_FLAG_FIXED_RATE))
 		return false;
 	list_for_each_entry(fp, &subs->fmt_list, list) {
-- 
2.39.0