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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 4889BC433F4 for ; Wed, 29 Aug 2018 08:13:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 086FA2089D for ; Wed, 29 Aug 2018 08:13:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 086FA2089D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=vmware.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728025AbeH2MJJ (ORCPT ); Wed, 29 Aug 2018 08:09:09 -0400 Received: from ex13-edg-ou-001.vmware.com ([208.91.0.189]:43187 "EHLO EX13-EDG-OU-001.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727477AbeH2MJI (ORCPT ); Wed, 29 Aug 2018 08:09:08 -0400 Received: from sc9-mailhost3.vmware.com (10.113.161.73) by EX13-EDG-OU-001.vmware.com (10.113.208.155) with Microsoft SMTP Server id 15.0.1156.6; Wed, 29 Aug 2018 01:13:09 -0700 Received: from sc2-haas01-esx0118.eng.vmware.com (sc2-haas01-esx0118.eng.vmware.com [10.172.44.118]) by sc9-mailhost3.vmware.com (Postfix) with ESMTP id 28AF740DAF; Wed, 29 Aug 2018 01:13:26 -0700 (PDT) From: Nadav Amit To: Thomas Gleixner CC: , Ingo Molnar , , Arnd Bergmann , , Nadav Amit , Andy Lutomirski , Masami Hiramatsu , Kees Cook Subject: [RFC PATCH 1/6] x86/alternative: assert text_mutex is taken Date: Wed, 29 Aug 2018 01:11:42 -0700 Message-ID: <20180829081147.184610-2-namit@vmware.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180829081147.184610-1-namit@vmware.com> References: <20180829081147.184610-1-namit@vmware.com> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: None (EX13-EDG-OU-001.vmware.com: namit@vmware.com does not designate permitted sender hosts) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use lockdep to ensure that text_mutex is taken when text_poke() is called. Actually it is not always taken, specifically when it is called by kgdb, so take the lock in these cases. Cc: Andy Lutomirski Cc: Masami Hiramatsu Cc: Kees Cook Suggested-by: Peter Zijlstra Signed-off-by: Nadav Amit --- arch/x86/kernel/alternative.c | 1 + arch/x86/kernel/kgdb.c | 9 +++++++++ 2 files changed, 10 insertions(+) diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 014f214da581..916c11b410c4 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -699,6 +699,7 @@ void *text_poke(void *addr, const void *opcode, size_t len) * pages as they are not yet initialized. */ BUG_ON(!after_bootmem); + lockdep_assert_held(&text_mutex); if (!core_kernel_text((unsigned long)addr)) { pages[0] = vmalloc_to_page(addr); diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 8e36f249646e..60b99c76086c 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -768,8 +768,12 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) */ if (mutex_is_locked(&text_mutex)) return -EBUSY; + + /* Take the mutex to avoid lockdep assertion failures. */ + mutex_lock(&text_mutex); text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); + mutex_unlock(&text_mutex); err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); if (err) return err; @@ -793,7 +797,12 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) */ if (mutex_is_locked(&text_mutex)) goto knl_write; + + /* Take the mutex to avoid lockdep assertion failures. */ + mutex_lock(&text_mutex); text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE); + mutex_unlock(&text_mutex); + err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE)) goto knl_write; -- 2.17.1