From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751313AbeAVR3S (ORCPT ); Mon, 22 Jan 2018 12:29:18 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:39001 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028AbeAVR3R (ORCPT ); Mon, 22 Jan 2018 12:29:17 -0500 From: Davidlohr Bueso To: tony.luck@intel.com, fenghua.yu@intel.com Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, Davidlohr Bueso Subject: [PATCH] ia64/err-inject: Use get_user_pages_fast() Date: Mon, 22 Jan 2018 09:21:37 -0800 Message-Id: <20180122172137.26849-1-dave@stgolabs.net> X-Mailer: git-send-email 2.13.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org At the point of sysfs callback, the call to gup is done without mmap_sem (or any lock for that matter). This is racy. As such, use the get_user_pages_fast() alternative and safely avoid taking the lock, if possible. Signed-off-by: Davidlohr Bueso --- arch/ia64/kernel/err_inject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/ia64/kernel/err_inject.c b/arch/ia64/kernel/err_inject.c index 85bba43e7d5d..658a8e06a69b 100644 --- a/arch/ia64/kernel/err_inject.c +++ b/arch/ia64/kernel/err_inject.c @@ -142,7 +142,7 @@ store_virtual_to_phys(struct device *dev, struct device_attribute *attr, u64 virt_addr=simple_strtoull(buf, NULL, 16); int ret; - ret = get_user_pages(virt_addr, 1, FOLL_WRITE, NULL, NULL); + ret = get_user_pages_fast(virt_addr, 1, FOLL_WRITE, NULL); if (ret<=0) { #ifdef ERR_INJ_DEBUG printk("Virtual address %lx is not existing.\n",virt_addr); -- 2.13.6