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=-15.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 70217C433ED for ; Mon, 12 Apr 2021 17:45:30 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 096F86124C for ; Mon, 12 Apr 2021 17:45:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 096F86124C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Plc5ZXRL+98fYFUI6A6SBYoakKH5VP7Zn8wwub4cRuY=; b=V8SxOKHToONSblGu2caJhu7Vr o6Y5Tv0PIxEj5gJ46hsKlQJqjkPHQ6mqSSv+WaYmjV1jvRp4GJOGFLbw4wiWLOgV8RodDVn6tWeQk 0Ofx0gs8xsHVQCiGe5MKnFAbiI9i8h0L9HYqsFjUg+VDOMAQlyyLgHevKhwMUrJgNzSPUqWLryYjH Fcu9Y3PNybi/MxcqXjHVwSMaXLrUlBpyazXoL1LLg6oGizu5A1MVV0kKqOIXJYeRoy8p77j0J190x 4+kzwQELC76v1Bzr85Jk29bXV8qnHNWe7b+TTMMJjB4x4c9obBiVDRsMMAt3BbYTr+BQRZJbMxtYw IqPlWMxQg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lW0bL-007NPo-QI; Mon, 12 Apr 2021 17:43:56 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lW0bH-007NPa-J7 for linux-arm-kernel@desiato.infradead.org; Mon, 12 Apr 2021 17:43:51 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=H10hLdmX/DwieDU2IXaPEeDOui1cMXEEL5pYaFzmc+0=; b=AKVP5vIjw2CTHlYk7Z3fkJGdnd 1lKXCO7nF99oDPeHMZLPLmWJlOkZ+yQyj0DL/4b1vKqpbrD130llQQBjIZ9nblIkzwpA0YEpYfDxg 2wY5oR1hAc41kKxcrPMbYQkWzTfVnhqZEr872ECJRoFhOUn7lJ6QDau3WUIlNnkcQ6GN0nq4KLap4 XRywa6Vu66uK5rR7ehzjnY4lwosp/d2ejO1iDXXgjW87E0ZvKA44FLeU8E4tbgdJRyYmWZ58vRNO9 Z1O9t6beGf6Os5bXUSyVHTo7uk9m1fLOEGqEm84OBpyPKXwRw1+1w60j4IwpZqRabzyMgaMrB3o98 JLv8QarA==; Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lW0bE-006Sc0-VO for linux-arm-kernel@lists.infradead.org; Mon, 12 Apr 2021 17:43:50 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id ADD5261354; Mon, 12 Apr 2021 17:43:46 +0000 (UTC) Date: Mon, 12 Apr 2021 18:43:44 +0100 From: Catalin Marinas To: Liam Howlett Cc: Andre Przywara , Will Deacon , Peter Collingbourne , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , "bpf@vger.kernel.org" , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Amit Daniel Kachhap Subject: Re: [PATCH] arch/arm64/kernel/traps: Use find_vma_intersection() in traps for setting si_code Message-ID: <20210412174343.GG2060@arm.com> References: <20210407150940.542103-1-Liam.Howlett@Oracle.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210407150940.542103-1-Liam.Howlett@Oracle.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210412_104349_050141_DF18A832 X-CRM114-Status: GOOD ( 21.61 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Apr 07, 2021 at 03:11:06PM +0000, Liam Howlett wrote: > find_vma() will continue to search upwards until the end of the virtual > memory space. This means the si_code would almost never be set to > SEGV_MAPERR even when the address falls outside of any VMA. The result > is that the si_code is not reliable as it may or may not be set to the > correct result, depending on where the address falls in the address > space. > > Using find_vma_intersection() allows for what is intended by only > returning a VMA if it falls within the range provided, in this case a > window of 1. > > Signed-off-by: Liam R. Howlett > --- > arch/arm64/kernel/traps.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c > index a05d34f0e82a..a44007904a64 100644 > --- a/arch/arm64/kernel/traps.c > +++ b/arch/arm64/kernel/traps.c > @@ -383,9 +383,10 @@ void force_signal_inject(int signal, int code, unsigned long address, unsigned i > void arm64_notify_segfault(unsigned long addr) > { > int code; > + unsigned long ut_addr = untagged_addr(addr); > > mmap_read_lock(current->mm); > - if (find_vma(current->mm, untagged_addr(addr)) == NULL) > + if (find_vma_intersection(current->mm, ut_addr, ut_addr + 1) == NULL) > code = SEGV_MAPERR; > else > code = SEGV_ACCERR; I don't think your change is entirely correct either. We can have a fault below the vma of a stack (with VM_GROWSDOWN) and find_vma_intersection() would return NULL but it should be a SEGV_ACCERR instead. Maybe this should employ similar checks as __do_page_fault() (with expand_stack() and VM_GROWSDOWN). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel