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(unknown [183.174.60.14]) by APP-05 (Coremail) with SMTP id zQCowADHzKBgONln2Q3vFQ--.5938S2; Tue, 18 Mar 2025 17:09:56 +0800 (CST) From: Ma Ke To: mchehab@kernel.org, hverkuil@xs4all.nl, make24@iscas.ac.cn, sebastian.fricke@collabora.com, ribalda@chromium.org, benjamin.gaignard@collabora.com, viro@zeniv.linux.org.uk, bartosz.golaszewski@linaro.org, hljunggr@cisco.com, sakari.ailus@linux.intel.com Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2] media: v4l2-dev: fix error handling in __video_register_device() Date: Tue, 18 Mar 2025 17:09:45 +0800 Message-Id: <20250318090945.1655458-1-make24@iscas.ac.cn> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: zQCowADHzKBgONln2Q3vFQ--.5938S2 X-Coremail-Antispam: 1UD129KBjvJXoW7WryrKw1xJF47CrWxtFW7CFg_yoW8CrWUp3 4xuayayrWUKw4IkwnxXFs8Z3Wruw4Sy3WrArWfAw40kwn3XrZ3tryvyryUX3y8trZ7AF4j qry2q3yrXF1Uu3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBY14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI 64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVWUJVW8Jw Am72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAG YxC7M4IIrI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7V AKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCj r7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6x IIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAI w20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x 0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUbQVy7UUUUU== X-CM-SenderInfo: ppdnvj2u6l2u1dvotugofq/ Content-Type: text/plain; charset="utf-8" Once device_register() failed, we should call put_device() to decrement reference count for cleanup. Or it could cause memory leak. And move callback function before put_device(). As comment of device_register() says, 'NOTE: _Never_ directly free @dev after calling this function, even if it returned an error! Always use put_device() to give up the reference initialized in this function instead.' Found by code review. Cc: stable@vger.kernel.org Fixes: baa057e29b58 ("media: v4l2-dev: use pr_foo() for printing messages") Signed-off-by: Ma Ke --- Changes in v2: - modified the patch as no callback function before put_device(). --- drivers/media/v4l2-core/v4l2-dev.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v= 4l2-dev.c index 5bcaeeba4d09..4a8fdf8115c0 100644 --- a/drivers/media/v4l2-core/v4l2-dev.c +++ b/drivers/media/v4l2-core/v4l2-dev.c @@ -1054,17 +1054,16 @@ int __video_register_device(struct video_device *vd= ev, vdev->dev.class =3D &video_class; vdev->dev.devt =3D MKDEV(VIDEO_MAJOR, vdev->minor); vdev->dev.parent =3D vdev->dev_parent; + vdev->dev.release =3D v4l2_device_release; dev_set_name(&vdev->dev, "%s%d", name_base, vdev->num); mutex_lock(&videodev_lock); ret =3D device_register(&vdev->dev); if (ret < 0) { mutex_unlock(&videodev_lock); pr_err("%s: device_register failed\n", __func__); - goto cleanup; + put_device(&vdev->dev); + return ret; } - /* Register the release callback that will be called when the last - reference to the device goes away. */ - vdev->dev.release =3D v4l2_device_release; =20 if (nr !=3D -1 && nr !=3D vdev->num && warn_if_nr_in_use) pr_warn("%s: requested %s%d, got %s\n", __func__, --=20 2.25.1