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[209.132.180.67]) by mx.google.com with ESMTP id z126-v6si23244454pfb.280.2018.11.13.10.22.44; Tue, 13 Nov 2018 10:23:10 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=hS3DOgAx; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729106AbeKNEVC (ORCPT + 99 others); Tue, 13 Nov 2018 23:21:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:39902 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726459AbeKNEVC (ORCPT ); Tue, 13 Nov 2018 23:21:02 -0500 Received: from devnote (unknown [64.114.255.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EBCB521582; Tue, 13 Nov 2018 18:21:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542133306; bh=nGZXDGtXuCpyXV0BdKWObyawac9dSFmS+6jhuTXTrc4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hS3DOgAxCvD5pVcjl4PV6ClC3OkEm12bWnbhs2m8QQGF5r/wAFymp9DoM2CwozFhd juaEn0uPL6OLR0JwqmYqMwchbN0OQAmM4rtcDbI/tQQyMY6I3dpwLaEE6QGxIKhj0B tZcfpv9mEEX2xnhtXdM7FmlFoggcLTnPJCbyKcGE= Date: Tue, 13 Nov 2018 10:21:45 -0800 From: Masami Hiramatsu To: Steven Rostedt Cc: Alexander Popov , Masami Hiramatsu , kernel-hardening@lists.openwall.com, Kees Cook , Jann Horn , Ingo Molnar , Andy Lutomirski , Joerg Roedel , Borislav Petkov , Thomas Gleixner , Dave Hansen , Peter Zijlstra , Jan Kara , Mathieu Desnoyers , Dan Williams , Masahiro Yamada , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] stackleak: Disable ftrace for stackleak.c Message-Id: <20181113102145.2274aedc6f9edaba681bfd3a@kernel.org> In-Reply-To: <20181112122148.0fab4c7f@vmware.local.home> References: <1541887530-16610-1-git-send-email-alex.popov@linux.com> <20181110183011.2290fc20@gandalf.local.home> <20181111205351.1874bb1e@vmware.local.home> <20181112115058.39e98750750c91eeb349cfdf@kernel.org> <31b45d77-7b49-3984-a1e5-17993f50eee3@linux.com> <20181112122148.0fab4c7f@vmware.local.home> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 12 Nov 2018 12:21:48 -0500 Steven Rostedt wrote: > On Mon, 12 Nov 2018 19:51:00 +0300 > Alexander Popov wrote: > > > By the way, are there any other tracing/instrumentation mechanisms that should > > be disabled? > > ftrace and kprobes are pretty much the only ones that currently do self > modification of code all over the kernel. Kprobes even more so than > ftrace. Right, since kprobes uses int3 or sw breakpoint exception for hooking into the code, it consumes stack much more. Thank you, -- Masami Hiramatsu