From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 207D8C43381 for ; Mon, 18 Mar 2019 06:43:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2911214D8 for ; Mon, 18 Mar 2019 06:43:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552891418; bh=rU/iHRxN7bFo6mkmI5rjfeZUhjBfRfMxbQW/mz8LX9g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=tMrL8lLQeoH8PLCT5Bu9ECpN9zPnrJmtmfEZVDgXBZccpt/rlZDDzEGHxX/mFqkdb xDHzZQi2EbmJmm9hBUp7pUI13G8mkoTsfiIWqmsoG+18uFqo7z3TfFT/jejl3Bbxw/ io29dSFM+AVvuyWXmM7I+u37XhTUJv4iqqOheCMM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727857AbfCRGnX (ORCPT ); Mon, 18 Mar 2019 02:43:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:41406 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727188AbfCRGnX (ORCPT ); Mon, 18 Mar 2019 02:43:23 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8520A20857; Mon, 18 Mar 2019 06:43:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552891402; bh=rU/iHRxN7bFo6mkmI5rjfeZUhjBfRfMxbQW/mz8LX9g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XYZPfSOOKlG0eAb8jLI94SmC2GJXRba46b6hDejyTcALHBgHc66IH3KgePevjMz8t MUVjY0BrNx0KIvPyFI+cM1JGRvvNXPY+p1vEV8oNCUSxNdZ+NuG2W45iDdT5H65+tZ Z5Ur+DfIclexvCGlXqRCvKVhyrWNx8sCq7OzaMSk= From: Masami Hiramatsu To: Steven Rostedt , Linus Torvalds , Shuah Khan , Arnaldo Carvalho de Melo , Peter Zijlstra Cc: mhiramat@kernel.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Ingo Molnar , Andrew Morton , Changbin Du , Jann Horn , Kees Cook , Andy Lutomirski , Alexei Starovoitov , Nadav Amit , Joel Fernandes , yhs@fb.com Subject: [RFC PATCH v6 1/6] x86/uaccess: Allow access_ok() in irq context if pagefault_disabled Date: Mon, 18 Mar 2019 15:43:17 +0900 Message-Id: <155289139725.7218.17265500814527931961.stgit@devnote2> X-Mailer: git-send-email 2.17.1 In-Reply-To: <155289137555.7218.9282784065958321058.stgit@devnote2> References: <155289137555.7218.9282784065958321058.stgit@devnote2> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org WARN_ON_IN_IRQ() assumes that the access_ok() and following user memory access can sleep. But this assumption is not always correct; when the pagefault is disabled, following memory access will just returns -EFAULT and never sleep. Add pagefault_disabled() check in WARN_ON_ONCE() so that it can ignore the case we call it with disabling pagefault. For this purpose, this modified pagefault_disabled() as an inline function. Signed-off-by: Masami Hiramatsu --- arch/x86/include/asm/uaccess.h | 4 +++- include/linux/uaccess.h | 5 ++++- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 1954dd5552a2..11581dc098d5 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -66,7 +66,9 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un }) #ifdef CONFIG_DEBUG_ATOMIC_SLEEP -# define WARN_ON_IN_IRQ() WARN_ON_ONCE(!in_task()) +static inline bool pagefault_disabled(void); +# define WARN_ON_IN_IRQ() \ + WARN_ON_ONCE(!in_task() && !pagefault_disabled()) #else # define WARN_ON_IN_IRQ() #endif diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 37b226e8df13..ef3032db1aef 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -203,7 +203,10 @@ static inline void pagefault_enable(void) /* * Is the pagefault handler disabled? If so, user access methods will not sleep. */ -#define pagefault_disabled() (current->pagefault_disabled != 0) +static inline bool pagefault_disabled(void) +{ + return current->pagefault_disabled != 0; +} /* * The pagefault handler is in general disabled by pagefault_disable() or