linux-kernel - Re: [syzbot] [sound?] [usb?] general protection fault in snd_usbmidi_do

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Message-Id: <20250927155052.880528-1-aha310510@gmail.com>
Date: Sun, 28 Sep 2025 00:50:52 +0900
From: Jeongjun Park <aha310510@...il.com>
To: syzbot+f02665daa2abeef4a947@...kaller.appspotmail.com
Cc: aha310510@...il.com,
	clemens@...isch.de,
	hdanton@...a.com,
	linux-kernel@...r.kernel.org,
	linux-sound@...r.kernel.org,
	perex@...ex.cz,
	syzkaller-bugs@...glegroups.com,
	tiwai@...e.de
Subject: Re: [syzbot] [sound?] [usb?] general protection fault in snd_usbmidi_do_output

syzbot <syzbot+f02665daa2abeef4a947@...kaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot has tested the proposed patch and the reproducer did not trigger any issue:
>
> Reported-by: syzbot+f02665daa2abeef4a947@...kaller.appspotmail.com
> Tested-by: syzbot+f02665daa2abeef4a947@...kaller.appspotmail.com
>
> Tested on:
>

#syz test upstream master

---
 sound/usb/midi.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index acb3bf92857c..97e7e7662b12 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -1522,15 +1522,14 @@ static void snd_usbmidi_free(struct snd_usb_midi *umidi)
 {
 	int i;
 
+	if (!umidi->disconnected)
+		snd_usbmidi_disconnect(&umidi->list);
+
 	for (i = 0; i < MIDI_MAX_ENDPOINTS; ++i) {
 		struct snd_usb_midi_endpoint *ep = &umidi->endpoints[i];
-		if (ep->out)
-			snd_usbmidi_out_endpoint_delete(ep->out);
-		if (ep->in)
-			snd_usbmidi_in_endpoint_delete(ep->in);
+		kfree(ep->out);
 	}
 	mutex_destroy(&umidi->mutex);
-	timer_shutdown_sync(&umidi->error_timer);
 	kfree(umidi);
 }
 
--