From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAF44275AFD; Wed, 9 Sep 2026 13:47:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788961670; cv=none; b=aBzIVE8Mzi3QeF/3bAMlx13lFB6beMAq/AotMNxm/Z5z73dDqmCzrR5RfNZpamr+lzahr4qP9hfQ56LypjykyNoByFwyRSuH87zajwy/QUiy4Lbt2iAclp3wYe2CXZdPBUK0/mDsecZ2+9JtP+aV3aek0Qo205575E6NxUur4P0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788961670; c=relaxed/simple; bh=M7uMxMzYLSaZY+9jjFC6GahXhnjQOe2sxBSxPSMj4a0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=L/S4Iao6EbkC2MR6kZBtYIKDl4EN/dpp/W9494QfrPa6I3XWKf6t/llOU/mKtL77AIdWcWGjT0VV4iXgUsD3x7/vs8GccPUiP39Gn7sJsD+DeiNI6oyUjTdX0nkGl7uASWVcAqKyYgGYbWb7VHyXVseEMLd1ZrXBfandapw+PrE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GbE/AXkJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GbE/AXkJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 274E61F00A3A; Wed, 9 Sep 2026 13:47:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788961669; bh=dd7//T+TRdaEPdW2hWiom7c+B7qnh9T9NLuVlQcqIWQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GbE/AXkJhS32S3sImh3+XltuwSUcrRp1b0EegNWoH9UnEJ+QCcGqbqrHEPnzSMFYe F0GWAiE6HZONbjKzT3hSPuGPGg5RX24MK+o9/zwg4Bd6xLO0ngsjROtEeb6yomMx7k qwaWXxDt1pz77VLbAjaSiuB3Cb4gXojML8l8mMIw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Shuangpeng Bai , Hans Verkuil Subject: [PATCH 7.2 028/556] media: usbtv: keep device alive while ALSA card exists Date: Wed, 9 Sep 2026 15:35:08 +0200 Message-ID: <20260909134231.496351220@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260909134230.441546314@linuxfoundation.org> References: <20260909134230.441546314@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shuangpeng Bai commit fc530fe168bb2b745a93f553ad21fc25fd9cba3d upstream. The ALSA PCM callbacks store the driver state in pcm->private_data. An open PCM file can outlive USB disconnect because usbtv_audio_free() uses snd_card_free_when_closed(). The disconnect path can then drop the V4L2 device reference and free struct usbtv before ALSA releases the substream, so a later close dereferences freed memory in snd_usbtv_pcm_close(). Take a V4L2 device reference for the ALSA card and drop it from the card private_free callback. This keeps struct usbtv valid until ALSA has closed the remaining files and freed the card. Closes: https://lore.kernel.org/r/178144969601.60470.4852887710381872458@gmail.com Fixes: 63ddf68de52e ("[media] usbtv: add audio support") Cc: stable@vger.kernel.org Signed-off-by: Shuangpeng Bai Signed-off-by: Hans Verkuil Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/usbtv/usbtv-audio.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/drivers/media/usb/usbtv/usbtv-audio.c +++ b/drivers/media/usb/usbtv/usbtv-audio.c @@ -317,6 +317,13 @@ static const struct snd_pcm_ops snd_usbt .pointer = snd_usbtv_pointer, }; +static void usbtv_audio_card_free(struct snd_card *card) +{ + struct usbtv *usbtv = card->private_data; + + v4l2_device_put(&usbtv->v4l2_dev); +} + int usbtv_audio_init(struct usbtv *usbtv) { int rv; @@ -331,6 +338,10 @@ int usbtv_audio_init(struct usbtv *usbtv if (rv < 0) return rv; + v4l2_device_get(&usbtv->v4l2_dev); + card->private_data = usbtv; + card->private_free = usbtv_audio_card_free; + strscpy(card->driver, usbtv->dev->driver->name, sizeof(card->driver)); strscpy(card->shortname, "usbtv", sizeof(card->shortname)); snprintf(card->longname, sizeof(card->longname),