From patchwork Fri Sep 29 11:27:41 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 9977543 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 37DA960311 for ; Fri, 29 Sep 2017 11:27:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1AA97297F1 for ; Fri, 29 Sep 2017 11:27:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0E3DE29824; Fri, 29 Sep 2017 11:27:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9BFB4297F1 for ; Fri, 29 Sep 2017 11:27:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=4xuuEtS28EPwxQ930Ps2qDVMmkXP6DB6LpMhmvsz6ts=; b=dPp OmawdTqjZmcqsM9eGupDQ5AxOWs5N7jydtbDbVnlyzrFsl7sloX57YK4R0SXXu635gl8XHb3bw/ZX o8VOG2kTdPgKAMwW5RXrISeHRY71V/EwZSywnNziqMxUdfR3r/QHSamF1UdUkck7EwUBg/TkfomJR a+KqqdyWc3hNoQAkY2TlMlh9hASx4c2QTVFmPk+Y13KeJ2n0+49N9G8pEtFnBOHrkqjxCwI4SR0Zo 5rQ67h8RdGMJJ+m/ve9UaxcW3T4Ckjcuek0UlyAxjGy789UZzK+OVqSxIARys8kDW8OvjRWUa4hCI ImX1EAuQ1Ltbo1extKhLeGgXJzBe5AA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1dxtSS-0000tu-6i; Fri, 29 Sep 2017 11:27:52 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1dxtSP-0000rD-6e for linux-arm-kernel@lists.infradead.org; Fri, 29 Sep 2017 11:27:50 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E57E61435; Fri, 29 Sep 2017 04:27:27 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B57943F53D; Fri, 29 Sep 2017 04:27:27 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 963601AE17BD; Fri, 29 Sep 2017 12:27:42 +0100 (BST) From: Will Deacon To: catalin.marinas@arm.com Subject: [PATCH] arm64: fault: Route pte translation faults via do_translation_fault Date: Fri, 29 Sep 2017 12:27:41 +0100 Message-Id: <1506684461-24162-1-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170929_042749_253655_758E0A90 X-CRM114-Status: GOOD ( 11.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Will Deacon , stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP We currently route pte translation faults via do_page_fault, which elides the address check against TASK_SIZE before invoking the mm fault handling code. However, this can cause issues with the path walking code in conjunction with our word-at-a-time implementation because load_unaligned_zeropad can end up faulting in kernel space if it reads across a page boundary and runs into a page fault (e.g. by attempting to read from a guard region). In the case of such a fault, load_unaligned_zeropad has registered a fixup to shift the valid data and pad with zeroes, however the abort is reported as a level 3 translation fault and we dispatch it straight to do_page_fault, despite it being a kernel address. This results in calling a sleeping function from atomic context: BUG: sleeping function called from invalid context at arch/arm64/mm/fault.c:313 in_atomic(): 0, irqs_disabled(): 0, pid: 10290 Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [...] [] ___might_sleep+0x134/0x144 [] __might_sleep+0x7c/0x8c [] do_page_fault+0x140/0x330 [] do_mem_abort+0x54/0xb0 Exception stack(0xfffffffb20247a70 to 0xfffffffb20247ba0) [...] [] el1_da+0x18/0x78 [] path_parentat+0x44/0x88 [] filename_parentat+0x5c/0xd8 [] filename_create+0x4c/0x128 [] SyS_mkdirat+0x50/0xc8 [] el0_svc_naked+0x24/0x28 Code: 36380080 d5384100 f9400800 9402566d (d4210000) ---[ end trace 2d01889f2bca9b9f ]--- Fix this by dispatching all translation faults to do_translation_faults, which avoids invoking the page fault logic for faults on kernel addresses. Cc: Reported-by: Ankit Jain Signed-off-by: Will Deacon --- arch/arm64/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 89993c4be1be..2069e9bc0fca 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -651,7 +651,7 @@ static const struct fault_info fault_info[] = { { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 0 translation fault" }, { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 1 translation fault" }, { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 2 translation fault" }, - { do_page_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, + { do_translation_fault, SIGSEGV, SEGV_MAPERR, "level 3 translation fault" }, { do_bad, SIGBUS, 0, "unknown 8" }, { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 access flag fault" }, { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 access flag fault" },