FAILED: patch "[PATCH] ALSA: wavefront: Clear substream pointers on close" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x e11c5c13ce0ab2325d38fe63500be1dd88b81e38
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025121601-unpopular-opulently-2ac5@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e11c5c13ce0ab2325d38fe63500be1dd88b81e38 Mon Sep 17 00:00:00 2001
From: Junrui Luo <moonafterrain@outlook.com>
Date: Thu, 6 Nov 2025 10:24:57 +0800
Subject: [PATCH] ALSA: wavefront: Clear substream pointers on close

Clear substream pointers in close functions to avoid leaving dangling
pointers, helping to improve code safety and
prevents potential issues.

Reported-by: Yuhao Jiang <danisjiang@gmail.com>
Reported-by: Junrui Luo <moonafterrain@outlook.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Junrui Luo <moonafterrain@outlook.com>
Link: https://patch.msgid.link/SYBPR01MB7881DF762CAB45EE42F6D812AFC2A@SYBPR01MB7881.ausprd01.prod.outlook.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/isa/wavefront/wavefront_midi.c b/sound/isa/wavefront/wavefront_midi.c
index 1250ecba659a..69d87c4cafae 100644
--- a/sound/isa/wavefront/wavefront_midi.c
+++ b/sound/isa/wavefront/wavefront_midi.c
@@ -278,6 +278,7 @@ static int snd_wavefront_midi_input_close(struct snd_rawmidi_substream *substrea
 	        return -EIO;
 
 	guard(spinlock_irqsave)(&midi->open);
+	midi->substream_input[mpu] = NULL;
 	midi->mode[mpu] &= ~MPU401_MODE_INPUT;
 
 	return 0;
@@ -300,6 +301,7 @@ static int snd_wavefront_midi_output_close(struct snd_rawmidi_substream *substre
 	        return -EIO;
 
 	guard(spinlock_irqsave)(&midi->open);
+	midi->substream_output[mpu] = NULL;
 	midi->mode[mpu] &= ~MPU401_MODE_OUTPUT;
 	return 0;
 }