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=-7.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 1845EC4360F for ; Thu, 21 Feb 2019 16:16:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4BC62084D for ; Thu, 21 Feb 2019 16:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550765808; bh=6Z60J6V8iIRle+JocqSM9UBFISn6DpwigjnmsrYpiGE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=AiO/lc2i8r9ZJqUh6EecedhBIhZ4u3y6KOBjrBsUhvP4ChdjNQzX2xaPbsWn3oLAf 8YxuLBftkgVVIuPXf8nrBeEWMrlN0y3sy6BdJ2Hz/u0M5fNvmWLg67XkEt8THsLhSO naBW7BBzPwkodKk7WaxXmXFwaiWkJI3B95YLtojo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbfBUQQr (ORCPT ); Thu, 21 Feb 2019 11:16:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:36146 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725943AbfBUQQr (ORCPT ); Thu, 21 Feb 2019 11:16:47 -0500 Received: from devbox (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 EE84C20836; Thu, 21 Feb 2019 16:16:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550765806; bh=6Z60J6V8iIRle+JocqSM9UBFISn6DpwigjnmsrYpiGE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=K6VU9BuY3UUT3bFcrnzUBckAtWv27p1NxOnh8FEGRrcBARkwhxIcFWxQipbw6Bnnj OKFCqAuIhaICGup7zITqfY5IHzDo7px2tzGayMur+AbHtoiugZlc5Adh/E5LXxVgqP +/vHRcqGGruQOc7h0F4IwkKpWOBpE68YOTi8fqGg= Date: Fri, 22 Feb 2019 01:16:43 +0900 From: Masami Hiramatsu To: Masami Hiramatsu Cc: Steven Rostedt , linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Andrew Morton , stable@vger.kernel.org, Changbin Du Subject: Re: [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access kernel memory that can fault Message-Id: <20190222011643.3e19ade84a3db3e83518648f@kernel.org> In-Reply-To: <20190222005812.04c5940c693b14cfdbe6ede7@kernel.org> References: <20190215174712.372898450@goodmis.org> <20190215174945.557218316@goodmis.org> <20190221165252.4a9033b3348f30f9d973dbc4@kernel.org> <20190221093625.56afccd2@gandalf.local.home> <20190222005812.04c5940c693b14cfdbe6ede7@kernel.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-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 Hi Steve, On Fri, 22 Feb 2019 00:58:12 +0900 Masami Hiramatsu wrote: > On Thu, 21 Feb 2019 09:36:25 -0500 > Steven Rostedt wrote: > > > On Thu, 21 Feb 2019 16:52:52 +0900 > > Masami Hiramatsu wrote: > > > > > Basically OK to me. > > > Could you use probe_kernel_read() in this context, since probe_mem_read() is a > > > wrapper function for template code. > > > > > > With that change, > > > > > > Acked-by: Masami Hiramatsu > > > > This already hit Linus's tree. I was able to reproduce the crash, so I > > streamlined it. I should have still pushed more for your ack first. > > Sorry about that. > > Oh, never mind. That seems urgent issue for kprobe event. > Thank you very much for fixing it! > > > For some reason, I thought the change was in the generic probe code, > > and accepted the probe_mem_read(). Anyway, did you want to send a patch > > to change it to probe_kernel_read(), for the merge window? > > No problem. Oops, I mean No, not yet. but it is a simple and cosmetic patch like below. Feel free to merge it to ftrace/core. --------- tracing/kprobes: Use probe_kernel_read instead of probe_mem_read From: Masami Hiramatsu Use probe_kernel_read() instead of probe_mem_read() because probe_mem_read() is a kind of wrapper for switching memory read function between uprobes and kprobes. Signed-off-by: Masami Hiramatsu --- kernel/trace/trace_kprobe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 9eaf07f99212..99592c27465e 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -865,7 +865,7 @@ fetch_store_strlen(unsigned long addr) u8 c; do { - ret = probe_mem_read(&c, (u8 *)addr + len, 1); + ret = probe_kernel_read(&c, (u8 *)addr + len, 1); len++; } while (c && ret == 0 && len < MAX_STRING_SIZE); -- Masami Hiramatsu