From patchwork Tue Mar 3 05:09:05 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Nan X-Patchwork-Id: 5919971 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id C20279F36A for ; Tue, 3 Mar 2015 05:13:46 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DEF51202B4 for ; Tue, 3 Mar 2015 05:13:45 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 13FA12027D for ; Tue, 3 Mar 2015 05:13:45 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSf6X-0006Tq-Ov; Tue, 03 Mar 2015 05:10:49 +0000 Received: from szxga02-in.huawei.com ([119.145.14.65]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1YSf6Q-00057i-TL for linux-arm-kernel@lists.infradead.org; Tue, 03 Mar 2015 05:10:44 +0000 Received: from 172.24.2.119 (EHLO lggeml425-hub.china.huawei.com) ([172.24.2.119]) by szxrg02-dlp.huawei.com (MOS 4.3.7-GA FastPath queued) with ESMTP id CHX55548; Tue, 03 Mar 2015 13:09:42 +0800 (CST) Received: from kernel-host.huawei (10.107.197.247) by lggeml425-hub.china.huawei.com (10.72.61.35) with Microsoft SMTP Server id 14.3.158.1; Tue, 3 Mar 2015 13:09:33 +0800 From: Wang Nan To: , , , , Subject: [PATCH 3/3] early kprobes: x86: don't try to recover ftraced instruction before ftrace get ready. Date: Tue, 3 Mar 2015 13:09:05 +0800 Message-ID: <1425359345-38714-4-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1425359345-38714-1-git-send-email-wangnan0@huawei.com> References: <1425306312-3437-1-git-send-email-wangnan0@huawei.com> <1425359345-38714-1-git-send-email-wangnan0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150302_211043_323051_1ADB19A9 X-CRM114-Status: UNSURE ( 7.16 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.3 (--) Cc: x86@kernel.org, lizefan@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Before ftrace convertin instruction to nop, if an early kprobe is registered then unregistered, without this patch its first bytes will be replaced by head of NOP, which may confuse ftrace. Actually, since we have a patch which convert ftrace entry to nop when probing, this problem should never be triggered. Provide it for safety. Signed-off-by: Wang Nan --- arch/x86/kernel/kprobes/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 87beb64..c7d304d 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -225,6 +225,9 @@ __recover_probed_insn(kprobe_opcode_t *buf, unsigned long addr) struct kprobe *kp; unsigned long faddr; + if (!kprobes_on_ftrace_initialized) + return addr; + kp = get_kprobe((void *)addr); faddr = ftrace_location(addr); /*