From nobody Mon Oct 6 15:24:12 2025 Received: from cstnet.cn (smtp81.cstnet.cn [159.226.251.81]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC71A1E9905; Sat, 19 Jul 2025 07:59:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.81 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752911957; cv=none; b=Yan/oN4IYXlWquj51/l6tzPxmuAtRzDnK4Mmq9/EHP735rWeZv6H8I2qpe6atb0oPldgm391vVmTTIp/SeneYcAmBD/5Tw4MX3puTZk0JBlGZUaH3AAakPjcgpthYXdrk6Da6gJGj/PGFF8+cmEcGgZmdWBsafwvjumMLJ9v66Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752911957; c=relaxed/simple; bh=CFyDh4S72NcYIkhbHgpug4yukC/Pb2g2Qpc43L+6ttw=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=luLG25PWSBtahnkcuYDhUeGcsSPjsR8+HOaF0D1U9kNp8M7utwN6sPiwFltb2NGojLtBMEYCm0lOPWVijE5MqqKmjHzEekpeRGG9hGYUgQ5lrovjOUCEkDK0HgS3gBwggFMEGuvoY8dReEM7OLC0vNu1NYXieUTucBUKb6SExXg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from icess-ProLiant-DL380-Gen10.. (unknown [211.71.28.34]) by APP-03 (Coremail) with SMTP id rQCowADXanxBUHtopMR8BQ--.10061S2; Sat, 19 Jul 2025 15:59:08 +0800 (CST) From: Ma Ke To: axboe@kernel.dk, Jim.Quigley@oracle.com, davem@davemloft.net, sln@onemain.com, alexandre.chartre@oracle.com, aaron.young@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 v2] sunvdc: Balance device refcount in vdc_port_mpgroup_check Date: Sat, 19 Jul 2025 15:58:56 +0800 Message-Id: <20250719075856.3447953-1-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: quoted-printable X-CM-TRANSID: rQCowADXanxBUHtopMR8BQ--.10061S2 X-Coremail-Antispam: 1UD129KBjvJXoW7tryDZw1xAr1kGFykXryrZwb_yoW8Jw4DpF 4DCa45ZrW5GF17Kr4kXa47ZryFka4jyryfWFWUAw1Yk3s3XryIyrWUt34jgw18JF93XFWD JF12yayrGFWDuaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUP014x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r4j6ryUM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4j 6F4UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVWxJr 0_GcWlnxkEFVAIw20F6cxK64vIFxWle2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xv F2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r 4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I 648v4I1lFIxGxcIEc7CjxVA2Y2ka0xkIwI1lc7CjxVAaw2AFwI0_Jw0_GFylc2xSY4AK67 AK6r4xMxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAF wI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc4 0Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AK xVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr 1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUbsmitUU UUU== 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=E2=80=99s 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 --- Changes in v2: - keep the change style simple as suggestions. --- drivers/block/sunvdc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c index b5727dea15bd..7af21fe67671 100644 --- a/drivers/block/sunvdc.c +++ b/drivers/block/sunvdc.c @@ -957,8 +957,10 @@ static bool vdc_port_mpgroup_check(struct vio_dev *vde= v) dev =3D device_find_child(vdev->dev.parent, &port_data, vdc_device_probed); =20 - if (dev) + if (dev) { + put_device(dev); return true; + } =20 return false; } --=20 2.25.1