Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752479AbaF0SdL (ORCPT ); Fri, 27 Jun 2014 14:33:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53720 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751374AbaF0SdI (ORCPT ); Fri, 27 Jun 2014 14:33:08 -0400 Date: Fri, 27 Jun 2014 19:01:36 +0200 From: Oleg Nesterov To: Steven Rostedt Cc: Masami Hiramatsu , Namhyung Kim , Srikar Dronamraju , Tom Zanussi , "zhangwei(Jovi)" , linux-kernel@vger.kernel.org Subject: [PATCH 1/4] tracing/uprobes: Revert "Support mix of ftrace and perf" Message-ID: <20140627170136.GA18319@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140627170116.GA18298@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This reverts commit 43fe98913c9f67e3b523615ee3316f9520a623e0. This patch is very wrong. Firstly, this change leads to unbalanced uprobe_unregister(). Just for example, # perf probe -x /lib/libc.so.6 syscall # echo 1 >> /sys/kernel/debug/tracing/events/probe_libc/enable # perf record -e probe_libc:syscall whatever after that uprobe is dead (unregistered) but the user of ftrace/perf can't know this, and it looks as if nobody hits this probe. This would be easy to fix, but there are other reasons why it is not simple to mix ftrace and perf. If nothing else, they can't share the same ->consumer.filter. This is fixable too, but probably we need to fix the poorly designed uprobe_register() interface first. At least "register" and "apply" should be clearly separated. Cc: stable@vger.kernel.org # v3.14 Signed-off-by: Oleg Nesterov --- kernel/trace/trace_uprobe.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 04fdb5d..08e7970 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -893,6 +893,9 @@ probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file, int ret; if (file) { + if (tu->tp.flags & TP_FLAG_PROFILE) + return -EINTR; + link = kmalloc(sizeof(*link), GFP_KERNEL); if (!link) return -ENOMEM; @@ -901,8 +904,12 @@ probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file, list_add_tail_rcu(&link->list, &tu->tp.files); tu->tp.flags |= TP_FLAG_TRACE; - } else + } else { + if (tu->tp.flags & TP_FLAG_TRACE) + return -EINTR; + tu->tp.flags |= TP_FLAG_PROFILE; + } ret = uprobe_buffer_enable(); if (ret < 0) -- 1.5.5.1 -- 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/