From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752803AbeDKDYN (ORCPT ); Tue, 10 Apr 2018 23:24:13 -0400 Received: from mail-pg0-f65.google.com ([74.125.83.65]:45221 "EHLO mail-pg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752103AbeDKDYL (ORCPT ); Tue, 10 Apr 2018 23:24:11 -0400 X-Google-Smtp-Source: AIpwx4+7+46jRhQI2IbE/C14uVgjz+vbxCawPqfpuipgnK9YBVOdsM77ZqfngdWmChbkhPs6InK0kA== From: Jia-Ju Bai To: mchehab@kernel.org Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Jia-Ju Bai Subject: [PATCH 2/3] media: dvb-usb: Replace GFP_ATOMIC with GFP_KERNEL in usb_bulk_urb_init Date: Wed, 11 Apr 2018 11:24:04 +0800 Message-Id: <1523417044-3115-1-git-send-email-baijiaju1990@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org usb_bulk_urb_init() is never called in atomic context. The call chains ending up at usb_bulk_urb_init() are: [1] usb_bulk_urb_init() <- usb_urb_init() <- dvb_usb_adapter_stream_init() <- dvb_usb_adapter_init <- dvb_usb_init() <- dvb_usb_device_init() <- xxx_probe() xxx_probe including ttusb2_probe, vp7045_usb_probe, a800_probe, and so on. These xxx_probe() functions are set as ".probe" in struct usb_driver. And these functions are not called in atomic context. Despite never getting called from atomic context, usb_bulk_urb_init() calls usb_alloc_urb() with GFP_ATOMIC, which does not sleep for allocation. GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, which can sleep and improve the possibility of sucessful allocation. This is found by a static analysis tool named DCNS written by myself. And I also manually check it. Signed-off-by: Jia-Ju Bai --- drivers/media/usb/dvb-usb/usb-urb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/usb/dvb-usb/usb-urb.c b/drivers/media/usb/dvb-usb/usb-urb.c index 8917360..d6d62e8 100644 --- a/drivers/media/usb/dvb-usb/usb-urb.c +++ b/drivers/media/usb/dvb-usb/usb-urb.c @@ -144,7 +144,7 @@ static int usb_bulk_urb_init(struct usb_data_stream *stream) /* allocate the URBs */ for (i = 0; i < stream->props.count; i++) { - stream->urb_list[i] = usb_alloc_urb(0, GFP_ATOMIC); + stream->urb_list[i] = usb_alloc_urb(0, GFP_KERNEL); if (!stream->urb_list[i]) { deb_mem("not enough memory for urb_alloc_urb!.\n"); for (j = 0; j < i; j++) -- 1.9.1