Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754125AbaJHS0G (ORCPT ); Wed, 8 Oct 2014 14:26:06 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:53067 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928AbaJHS0E (ORCPT ); Wed, 8 Oct 2014 14:26:04 -0400 From: Jason Gerecke To: jkosina@suse.cz, benjamin.tissoires@gmail.com, pinglinux@gmail.com Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Jason Gerecke Subject: [PATCH v2] HID: wacom: Prevent potential null dereference after disconnect Date: Wed, 8 Oct 2014 11:25:42 -0700 Message-Id: <1412792742-4075-1-git-send-email-killertofu@gmail.com> X-Mailer: git-send-email 2.1.2 In-Reply-To: <1412704473-6708-1-git-send-email-killertofu@gmail.com> References: <1412704473-6708-1-git-send-email-killertofu@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Repeated connect/disconnect cycles under GNOME can trigger an occasional OOPS from within e.g. wacom_led_select_store, presumably due to a timing issue where userspace begins setting a value immediately before the device disconnects and our shared data is whisked away. Signed-off-by: Jason Gerecke --- Changes in v2: * Added in missing escape character drivers/hid/wacom_sys.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/hid/wacom_sys.c b/drivers/hid/wacom_sys.c index 8593047..265429b 100644 --- a/drivers/hid/wacom_sys.c +++ b/drivers/hid/wacom_sys.c @@ -641,6 +641,9 @@ static ssize_t wacom_led_select_store(struct device *dev, int set_id, unsigned int id; int err; + if (!wacom) + return -ENODEV; + err = kstrtouint(buf, 10, &id); if (err) return err; @@ -666,6 +669,8 @@ static ssize_t wacom_led##SET_ID##_select_show(struct device *dev, \ { \ struct hid_device *hdev = container_of(dev, struct hid_device, dev);\ struct wacom *wacom = hid_get_drvdata(hdev); \ + if (!wacom) \ + return -ENODEV; \ return scnprintf(buf, PAGE_SIZE, "%d\n", \ wacom->led.select[SET_ID]); \ } \ @@ -702,7 +707,8 @@ static ssize_t wacom_##name##_luminance_store(struct device *dev, \ { \ struct hid_device *hdev = container_of(dev, struct hid_device, dev);\ struct wacom *wacom = hid_get_drvdata(hdev); \ - \ + if (!wacom) \ + return -ENODEV; \ return wacom_luminance_store(wacom, &wacom->led.field, \ buf, count); \ } \ @@ -710,6 +716,8 @@ static ssize_t wacom_##name##_luminance_show(struct device *dev, \ struct device_attribute *attr, char *buf) \ { \ struct wacom *wacom = dev_get_drvdata(dev); \ + if (!wacom) \ + return -ENODEV; \ return scnprintf(buf, PAGE_SIZE, "%d\n", wacom->led.field); \ } \ static DEVICE_ATTR(name##_luminance, DEV_ATTR_RW_PERM, \ @@ -729,6 +737,9 @@ static ssize_t wacom_button_image_store(struct device *dev, int button_id, unsigned len; u8 xfer_id; + if (!wacom) + return -ENODEV; + if (hdev->bus == BUS_BLUETOOTH) { len = 256; xfer_id = WAC_CMD_ICON_BT_XFER; -- 2.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/