Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966379AbbBCQUk (ORCPT ); Tue, 3 Feb 2015 11:20:40 -0500 Received: from cantor2.suse.de ([195.135.220.15]:44072 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965830AbbBCQUj (ORCPT ); Tue, 3 Feb 2015 11:20:39 -0500 From: Petr Mladek To: Masami Hiramatsu , "David S. Miller" , Anil S Keshavamurthy , Ananth NMavinakayanahalli , Frederic Weisbecker Cc: Steven Rostedt , Jiri Kosina , linux-kernel@vger.kernel.org, Petr Mladek Subject: [PATCH] kprobes/x86: Check for invalid ftrace location in __recover_probed_insn() Date: Tue, 3 Feb 2015 17:21:53 +0100 Message-Id: <1422980513-19327-1-git-send-email-pmladek@suse.cz> X-Mailer: git-send-email 1.8.5.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1661 Lines: 44 __recover_probed_insn() should always be called from an address where an instructions starts. The check for ftrace_location() might help to discover a potential inconsistency. Something goes terribly wrong when an address inside the ftrace location is checked. Let's BUG() in this case. Suggested-by: Masami Hiramatsu Signed-off-by: Petr Mladek --- arch/x86/kernel/kprobes/core.c | 6 ++++++ 1 file changed, 6 insertions(+) This is follow up for the patch ("[PATCH v2] kprobes/x86: Use 5-byte NOP when the code might be modified by ftrace") based on the Masami's suggestion, see https://lkml.org/lkml/2015/2/3/207 Let me know if I should merge this with the first patch and send v3. diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 2f464b56766a..124577dcf768 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -228,6 +228,12 @@ __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) kp = get_kprobe((void *)addr); faddr = ftrace_location(addr); /* + * Addresses inside the ftrace location are refused by + * arch_check_ftrace_location(). Something went terribly wrong + * if such an address is checked here. + */ + BUG_ON(faddr && faddr != addr); + /* * Use the current code if it is not modified by Kprobe * and it cannot be modified by ftrace. */ -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/