From patchwork Wed Mar 20 11:08:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Wetzel X-Patchwork-Id: 781467 Received: from ns2.wdyn.eu (ns2.wdyn.eu [5.252.227.236]) by smtp.subspace.kernel.org (Postfix) with ESMTP id E7DB83B298; Wed, 20 Mar 2024 11:08:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=5.252.227.236 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710932927; cv=none; b=mAw7DIKnC9YfWit7yK6sNW+9gPbqmhsIi2UL00mzmND+22m/VAMwc620o1jDeYZs8Zi1KKxHZhbVRJlpwLA9qJ34nANwThIQNJH1XtDnjhMlG2cVWDnPJ8tmv8Yn2ezBwn45KuW+2faXjGdwKCgrovDg/fZqailc56zkzzZq2CQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710932927; c=relaxed/simple; bh=/Mf7ayfRptIPYf1l912/MT+uiDe4k/RTJV5IF4l5F5E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PEt0zNtVs9bXlhBnQ76m7Tej7l4BjFUoZ8hhHDjY77XE4d+z44/G177HOafhYXNwaCWOLBYz0mvEdYyeObYMhGUJcQRCv53JHPF0LDdzRL0T8vSALDDoHQlQkYuwlrebJAlnjATTQ/7RDvKIkz2XoZK8hCYlsvbQ6ekJdTuBzhk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wetzel-home.de; spf=pass smtp.mailfrom=wetzel-home.de; dkim=pass (1024-bit key) header.d=wetzel-home.de header.i=@wetzel-home.de header.b=QQ/sZ5Xx; arc=none smtp.client-ip=5.252.227.236 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wetzel-home.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wetzel-home.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=wetzel-home.de header.i=@wetzel-home.de header.b="QQ/sZ5Xx" From: Alexander Wetzel DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=wetzel-home.de; s=wetzel-home; t=1710932914; bh=/Mf7ayfRptIPYf1l912/MT+uiDe4k/RTJV5IF4l5F5E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QQ/sZ5XxSexkc6olD8pvqKZbcXusVtWNm0EPZ5q8k3loqGxLngGx6B0e4guPyFmgO h2qgbe+6RO2h4GPnFjSahMhjBFvdePvMwmaFWPlsGvoLi1lu2+srW8lsJP7GrZX/hx 9bcZ2X/mj1C0GbLb5Os3v98EKUIEAOd0BHqYNNpc= To: dgilbert@interlog.com Cc: linux-scsi@vger.kernel.org, Alexander Wetzel , stable@vger.kernel.org Subject: [PATCH v2] scsi: sg: Avoid sg device teardown race Date: Wed, 20 Mar 2024 12:08:09 +0100 Message-ID: <20240320110809.12901-1-Alexander@wetzel-home.de> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240318175021.22739-1-Alexander@wetzel-home.de> References: <20240318175021.22739-1-Alexander@wetzel-home.de> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 sg_remove_sfp_usercontext() must not use sg_device_destroy() after calling scsi_device_put(). sg_device_destroy() is accessing the parent scsi device request_queue. Which will already be set to NULL when the preceding call to scsi_device_put() removed the last reference to the parent scsi device. The resulting NULL pointer exception will then crash the kernel. Link: https://lore.kernel.org/r/20240305150509.23896-1-Alexander@wetzel-home.de Cc: Signed-off-by: Alexander Wetzel Reviewed-by: Bart Van Assche --- Changes compared to V1: Reworked the commit message Alexander --- drivers/scsi/sg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 86210e4dd0d3..80e0d1981191 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -2232,8 +2232,8 @@ sg_remove_sfp_usercontext(struct work_struct *work) "sg_remove_sfp: sfp=0x%p\n", sfp)); kfree(sfp); - scsi_device_put(sdp->device); kref_put(&sdp->d_ref, sg_device_destroy); + scsi_device_put(sdp->device); module_put(THIS_MODULE); }