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(unknown [211.71.28.34]) by APP-01 (Coremail) with SMTP id qwCowAB3oKROBHpo+xghBQ--.35899S2; Fri, 18 Jul 2025 16:22:47 +0800 (CST) From: Ma Ke To: axboe@kernel.dk, sln@onemain.com, Jim.Quigley@oracle.com, liam.merwick@oracle.com, aaron.young@oracle.com, alexandre.chartre@oracle.com Cc: akpm@linux-foundation.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Ma Ke , stable@vger.kernel.org Subject: [PATCH] sunvdc: Balance device refcount in vdc_port_mpgroup_check Date: Fri, 18 Jul 2025 16:22:36 +0800 Message-Id: <20250718082236.3400483-1-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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CM-TRANSID:qwCowAB3oKROBHpo+xghBQ--.35899S2 X-Coremail-Antispam: 1UD129KBjvJXoW7tryDZw1xAr1kGFykXryrZwb_yoW8WF48pa 1DCa45XrW3GF17Kr48XayUZF1FkFy0v34SgFW8Aw1Fkr93XrWIyrWUt34j9w1UJF93JFWD JF17ta48JFWUXaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPj14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAac4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IE rcIFxwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCY02Avz4vE14 v_GFyl42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AK xVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r43MIIYrx kI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v2 6r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJVW8Jw CI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjfUeYLvDUUU U X-CM-SenderInfo: ppdnvj2u6l2u1dvotugofq/ Using device_find_child() to locate a probed virtual-device-port node causes a device refcount imbalance, as device_find_child() internally calls get_device() to increment the device’s reference count before returning its pointer. vdc_port_mpgroup_check() directly returns true upon finding a matching device without releasing the reference via put_device(). We should call put_device() to decrement refcount. As comment of device_find_child() says, 'NOTE: you will need to drop the reference with put_device() after use'. Found by code review. Cc: stable@vger.kernel.org Fixes: 3ee70591d6c4 ("sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain") Signed-off-by: Ma Ke --- drivers/block/sunvdc.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c index b5727dea15bd..b6dbd5dd2723 100644 --- a/drivers/block/sunvdc.c +++ b/drivers/block/sunvdc.c @@ -950,6 +950,7 @@ static bool vdc_port_mpgroup_check(struct vio_dev *vdev) { struct vdc_check_port_data port_data; struct device *dev; + bool found = false; port_data.dev_no = vdev->dev_no; port_data.type = (char *)&vdev->type; @@ -957,10 +958,12 @@ static bool vdc_port_mpgroup_check(struct vio_dev *vdev) dev = device_find_child(vdev->dev.parent, &port_data, vdc_device_probed); - if (dev) - return true; + if (dev) { + found = true; + put_device(dev); + } - return false; + return found; } static int vdc_port_probe(struct vio_dev *vdev, const struct vio_device_id *id) -- 2.25.1