From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:40508 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1163193AbeE1KvB (ORCPT ); Mon, 28 May 2018 06:51:01 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Davidlohr Bueso , Tony Luck , Sasha Levin Subject: [PATCH 4.14 219/496] ia64/err-inject: Use get_user_pages_fast() Date: Mon, 28 May 2018 12:00:04 +0200 Message-Id: <20180528100329.144911866@linuxfoundation.org> In-Reply-To: <20180528100319.498712256@linuxfoundation.org> References: <20180528100319.498712256@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Davidlohr Bueso [ Upstream commit 69c907022a7d9325cdc5c9dd064571e445df9a47 ] 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 Signed-off-by: Tony Luck Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/ia64/kernel/err_inject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- 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 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);