From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 38DA4481FC2 for ; Fri, 21 Aug 2026 14:24:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787322301; cv=none; b=ZQD1gpb8nCBDFZyB501hf2Vh8L53mSEVjnj+dngGYtVwrmVDreycUImz0htVHLOV2sGL8QtqZX7FYuuNqdsPc6/Q+vP95+sVhSTRAeLgaakmWdFMKn8F/xo9kEAwSJRk/6XN9oT+oRlKwDgOr9Ae6Ei2ZF1YAIVBENdrzfpsU8A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787322301; c=relaxed/simple; bh=CvVkhhBXZG0ZDrJsnmBXLSGYgGyIZi2GM0825+aHLdA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=PzV8IG/+B4YZydtpK0Hdm10R9dLDxrGtxiuQrKSjjP3dNB6h2Z0fIo/2gnGhAuH5ibTpIWx9TeV8y2+O6QEJWMwHhxDkaCmiB8kH61kC4eyhfmghCaLcL2Ht37vfpRBPPjza82pOVCYInO3qCt3U86V1bsFvZ/SkhyMir7xaHJM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=igV22lKu; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="igV22lKu" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787322295; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=S4w5b49VFjE4E0AFoA0Qcj7jylDcxSilk3hvFC5nqKA=; b=igV22lKub7cfoQ6OvZL3nlhIS/or6X+lTFw4IQQYOxo1RfLOgoA51FoodWHtQTM/Gr6A9S FutoMraPLqwc0QnrGgnp4BXcl9gO9fEgtAg6Cjk72tsl4wARtZnQ+j0TDZ5fS5KHMrqM6K Sl48gOP60Nd4SV0M26MnCJi5g6TlQcE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-235-0DWkU8VlPs6IoD1cwnQOkQ-1; Fri, 21 Aug 2026 10:24:49 -0400 X-MC-Unique: 0DWkU8VlPs6IoD1cwnQOkQ-1 X-Mimecast-MFC-AGG-ID: 0DWkU8VlPs6IoD1cwnQOkQ_1787322288 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4B37F1801BEC; Fri, 21 Aug 2026 14:24:47 +0000 (UTC) Received: from djeffery-thinkpadp1gen3.redhat.corp (headnet05.pony-001.prod.iad2.dc.redhat.com [10.2.32.117]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A50C11800346; Fri, 21 Aug 2026 14:24:44 +0000 (UTC) From: David Jeffery To: driver-core@lists.linux.dev, Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, Tarun Sahu , Stuart Hayes , Laurence Oberman , Bjorn Helgaas , kexec@lists.infradead.org, David Jeffery Subject: [PATCH 1/9] driver core: rely on put_device to free dev->p Date: Fri, 21 Aug 2026 10:24:06 -0400 Message-ID: <20260821142414.150892-2-djeffery@redhat.com> In-Reply-To: <20260821142414.150892-1-djeffery@redhat.com> References: <20260821142414.150892-1-djeffery@redhat.com> Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Mimecast-MFC-PROC-ID: tZEkE86SCfdN7G6eS70W3VmgAMj_5sAyntFaMjgBt7Q_1787322288 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true From: Tarun Sahu device_add allocate private_data for device and assigns to dev->p. If device_add fails in later steps of the function, it cleans up this dev->p which is not necessary because In the next call, put_device free it anyway (if reference to the device is 0 which will be unless someone concurrently get the reference to this device). This avoids unnecessary races introduced in system. After device is added in device_kset->list by device_add and later steps in the device_add function failures occur, it will free dev->p manually, while in between there might be a user of device_kset->list will take reference to the device just added by device_add. and might try to access dev->p. So relying on put_device to free dev->p prevents such problem. Signed-off-by: Tarun Sahu Signed-off-by: David Jeffery Tested-by: Laurence Oberman --- drivers/base/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 4c0c373998a1..83263e3fa5d4 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -2618,6 +2618,7 @@ static void device_release(struct kobject *kobj) struct device *dev = kobj_to_dev(kobj); struct device_private *p = dev->p; + dev->p = NULL; /* * Some platform devices are driven without driver attached * and managed resources may have been acquired. Make sure @@ -3828,8 +3829,6 @@ int device_add(struct device *dev) parent_error: put_device(parent); name_error: - kfree(dev->p); - dev->p = NULL; goto done; } EXPORT_SYMBOL_GPL(device_add); -- 2.55.0