From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932145AbeALAuU (ORCPT + 1 other); Thu, 11 Jan 2018 19:50:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:56184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932514AbeALAsY (ORCPT ); Thu, 11 Jan 2018 19:48:24 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 675652177B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Message-Id: <20180112004822.403349289@goodmis.org> User-Agent: quilt/0.63-1 Date: Thu, 11 Jan 2018 19:47:46 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Arnaldo Carvalho de Melo , Ingo Molnar , Andrew Morton , Namhyung Kim Subject: [PATCH 05/10] lib traceevent: Handle new pointer processing of bprint strings References: <20180112004741.378806573@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0005-lib-traceevent-Handle-new-pointer-processing-of-bpri.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: "Steven Rostedt (VMware)" The Linux kernel printf() has some extended use cases that dereference the pointer. This is dangerouse for tracing because the pointer that is dereferenced can change or even be unmapped. It also causes issues when the trace data is extracted, because user space does not have access to the contents of the pointer even if it still exists. To handle this, the kernel was updated to process these dereferenced pointers at the time they are recorded, and not post processed. Now they exist in the tracing buffer, and no dereference is needed at the time of reading the trace. The event parsing library needs to handle this new case. Signed-off-by: Steven Rostedt (VMware) --- tools/lib/traceevent/event-parse.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c index 8757dd64e42c..344a034a8fbc 100644 --- a/tools/lib/traceevent/event-parse.c +++ b/tools/lib/traceevent/event-parse.c @@ -4300,6 +4300,26 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc goto process_again; case 'p': ls = 1; + if (isalnum(ptr[1])) { + ptr++; + /* Check for special pointers */ + switch (*ptr) { + case 's': + case 'S': + case 'f': + case 'F': + break; + default: + /* + * Older kernels do not process + * dereferenced pointers. + * Only process if the pointer + * value is a printable. + */ + if (isprint(*(char *)bptr)) + goto process_string; + } + } /* fall through */ case 'd': case 'u': @@ -4352,6 +4372,7 @@ static struct print_arg *make_bprint_args(char *fmt, void *data, int size, struc break; case 's': + process_string: arg = alloc_arg(); if (!arg) { do_warning_event(event, "%s(%d): not enough memory!", @@ -4959,6 +4980,11 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct event if (isalnum(ptr[1])) ptr++; + if (arg->type == PRINT_BSTRING) { + trace_seq_puts(s, arg->string.string); + break; + } + if (*ptr == 'F' || *ptr == 'f' || *ptr == 'S' || *ptr == 's') { show_func = *ptr; -- 2.13.2