From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753611AbaCBP5N (ORCPT ); Sun, 2 Mar 2014 10:57:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:26489 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752476AbaCBP5K (ORCPT ); Sun, 2 Mar 2014 10:57:10 -0500 From: Jiri Olsa To: linux-kernel@vger.kernel.org Cc: Jiri Olsa , Peter Zijlstra , Paul Mackerras , Ingo Molnar , Arnaldo Carvalho de Melo , "H. Peter Anvin" , Vince Weaver , Steven Rostedt Subject: [PATCH 1/3] perf: Disallow user space callchains for function trace event Date: Sun, 2 Mar 2014 16:56:38 +0100 Message-Id: <1393775800-13524-2-git-send-email-jolsa@redhat.com> In-Reply-To: <1393775800-13524-1-git-send-email-jolsa@redhat.com> References: <1393775800-13524-1-git-send-email-jolsa@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Disabling user callchains for function trace event. Recent issues with user space callchains processing within page fault handler tracing showed as Peter said 'there's just too much fail surface'. Related list discussions: http://marc.info/?t=139302086500001&r=1&w=2 http://marc.info/?t=139301437300003&r=1&w=2 Suggested-by: Peter Zijlstra Signed-off-by: Jiri Olsa Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: H. Peter Anvin Cc: Vince Weaver Cc: Steven Rostedt --- kernel/trace/trace_event_perf.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index e854f42..d5e01c3 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -31,9 +31,18 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event, } /* The ftrace function trace is allowed only for root. */ - if (ftrace_event_is_function(tp_event) && - perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN)) - return -EPERM; + if (ftrace_event_is_function(tp_event)) { + if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* + * We don't allow user space callchains for function trace + * event, due to issues with page faults while tracing page + * fault handler and its overall trickiness nature. + */ + if (!p_event->attr.exclude_callchain_user) + return -EINVAL; + } /* No tracing, just counting, so no obvious leak */ if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW)) -- 1.8.3.1