From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sun, 10 Sep 2017 00:27:19 +0200 (CEST) Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:38623 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23994830AbdIIWY7L8crF (ORCPT ); Sun, 10 Sep 2017 00:24:59 +0200 Received: from [2a02:8011:400e:2:6f00:88c8:c921:d332] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1dqoBL-00014X-HY; Sat, 09 Sep 2017 23:24:56 +0100 Received: from ben by deadeye with local (Exim 4.89) (envelope-from ) id 1dqoBF-0006vE-DL; Sat, 09 Sep 2017 23:24:49 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, linux-mips@linux-mips.org, "Ralf Baechle" , "Marcin Nowakowski" Date: Sat, 09 Sep 2017 22:47:15 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 171/233] MIPS: kprobes: flush_insn_slot should flush only if probe initialised In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 59976 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ben@decadent.org.uk Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips 3.16.48-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Marcin Nowakowski commit 698b851073ddf5a894910d63ca04605e0473414e upstream. When ftrace is used with kprobes, it is possible for a kprobe to contain an invalid location (ie. only initialised to 0 and not to a specific location in the code). Trying to perform a cache flush on such location leads to a crash r4k_flush_icache_range(). Fixes: c1bf207d6ee1 ("MIPS: kprobe: Add support.") Signed-off-by: Marcin Nowakowski Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16296/ Signed-off-by: Ralf Baechle Signed-off-by: Ben Hutchings --- arch/mips/include/asm/kprobes.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/mips/include/asm/kprobes.h +++ b/arch/mips/include/asm/kprobes.h @@ -40,7 +40,8 @@ typedef union mips_instruction kprobe_op #define flush_insn_slot(p) \ do { \ - flush_icache_range((unsigned long)p->addr, \ + if (p->addr) \ + flush_icache_range((unsigned long)p->addr, \ (unsigned long)p->addr + \ (MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \ } while (0)