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[59.190.207.251]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b2d4f2af90sm13532835ad.64.2026.04.09.22.00.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Apr 2026 22:00:23 -0700 (PDT) From: Berk Cem Goksel To: Takashi Iwai , Jaroslav Kysela Cc: linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, Andrey Konovalov , Berk Cem Goksel , stable@vger.kernel.org Subject: [PATCH 2/2] ALSA: caiaq: take a reference on the USB device in create_card() Date: Fri, 10 Apr 2026 07:59:04 +0300 Message-Id: <20260410045904.1064020-3-berkcgoksel@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260410045904.1064020-1-berkcgoksel@gmail.com> References: <20260410045904.1064020-1-berkcgoksel@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The caiaq driver stores a pointer to the parent USB device in cdev->chip.dev but never takes a reference on it. The card's private_free callback, snd_usb_caiaq_card_free(), can run asynchronously via snd_card_free_when_closed() after the USB device has already been disconnected and freed, so any access to cdev->chip.dev in that path dereferences a freed usb_device. On top of the refcounting issue, the current card_free implementation calls usb_reset_device(cdev->chip.dev). A reset in a free callback is inappropriate: the device is going away, the call takes the device lock in a teardown context, and the reset races with the disconnect path that the callback is already cleaning up after. Take a reference on the USB device in create_card() with usb_get_dev(), drop it with usb_put_dev() in the free callback, and remove the usb_reset_device() call. Fixes: 523f1dce7096 ("ALSA: snd-usb-caiaq: add support for NI Audio Kontrol 1") Cc: stable@vger.kernel.org Cc: Andrey Konovalov Signed-off-by: Berk Cem Goksel --- sound/usb/caiaq/device.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/sound/usb/caiaq/device.c b/sound/usb/caiaq/device.c --- a/sound/usb/caiaq/device.c +++ b/sound/usb/caiaq/device.c @@ -385,7 +385,8 @@ snd_usb_caiaq_input_free(cdev); #endif snd_usb_caiaq_audio_free(cdev); - usb_reset_device(cdev->chip.dev); + if (cdev->chip.dev) + usb_put_dev(cdev->chip.dev); } static int create_card(struct usb_device *usb_dev, @@ -411,7 +412,7 @@ return err; cdev = caiaqdev(card); - cdev->chip.dev = usb_dev; + cdev->chip.dev = usb_get_dev(usb_dev); cdev->chip.card = card; cdev->chip.usb_id = USB_ID(le16_to_cpu(usb_dev->descriptor.idVendor), le16_to_cpu(usb_dev->descriptor.idProduct));