From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752805AbdJCNNo (ORCPT ); Tue, 3 Oct 2017 09:13:44 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60050 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752336AbdJCMWR (ORCPT ); Tue, 3 Oct 2017 08:22:17 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ankit Jain , Will Deacon , Catalin Marinas Subject: [PATCH 4.4 23/41] arm64: fault: Route pte translation faults via do_translation_fault Date: Tue, 3 Oct 2017 14:21:24 +0200 Message-Id: <20171003114221.304176541@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171003114219.900672076@linuxfoundation.org> References: <20171003114219.900672076@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Will Deacon commit 760bfb47c36a07741a089bf6a28e854ffbee7dc9 upstream. 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. Reported-by: Ankit Jain Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -447,7 +447,7 @@ static struct 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" },