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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=ham 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 73B92C74A21 for ; Wed, 10 Jul 2019 16:01:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F4342064A for ; Wed, 10 Jul 2019 16:01:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728257AbfGJQBN (ORCPT ); Wed, 10 Jul 2019 12:01:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:40974 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727463AbfGJQBM (ORCPT ); Wed, 10 Jul 2019 12:01:12 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 5C1F32064A; Wed, 10 Jul 2019 16:01:11 +0000 (UTC) Date: Wed, 10 Jul 2019 12:01:10 -0400 From: Steven Rostedt To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, LKML Cc: Ville =?UTF-8?B?U3lyasOkbMOk?= , Maarten Lankhorst , David Airlie , Daniel Vetter Subject: [PATCH] drm/i915: Copy name string into ring buffer for intel_update/disable_plane tracepoints Message-ID: <20190710120110.17394e73@gandalf.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; 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 From: "Steven Rostedt (VMware)" Currently the intel_update_plane and intel_disable_plane tracepoints record the address of plane->name in the ring buffer, and then when reading the ring buffer uses %s to get the name. The issue with this, is that those two events can be minutes, hours or even days apart. It is very dangerous to dereference a string pointer without knowing if it still exists or not. The proper way to handle this is to use the __string() macro in the tracepoint which will save the string into the ring buffer at the time of recording. Then there's no worries if the original string still exists in memory when the ring buffer is read. Signed-off-by: Steven Rostedt (VMware) --- drivers/gpu/drm/i915/i915_trace.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h index 12893304c8f8..d41d914a16ca 100644 --- a/drivers/gpu/drm/i915/i915_trace.h +++ b/drivers/gpu/drm/i915/i915_trace.h @@ -298,16 +298,16 @@ TRACE_EVENT(intel_update_plane, TP_STRUCT__entry( __field(enum pipe, pipe) - __field(const char *, name) __field(u32, frame) __field(u32, scanline) __array(int, src, 4) __array(int, dst, 4) + __string(name, plane->name) ), TP_fast_assign( + __assign_str(name, plane->name); __entry->pipe = crtc->pipe; - __entry->name = plane->name; __entry->frame = crtc->base.dev->driver->get_vblank_counter(crtc->base.dev, crtc->pipe); __entry->scanline = intel_get_crtc_scanline(crtc); @@ -316,7 +316,7 @@ TRACE_EVENT(intel_update_plane, ), TP_printk("pipe %c, plane %s, frame=%u, scanline=%u, " DRM_RECT_FP_FMT " -> " DRM_RECT_FMT, - pipe_name(__entry->pipe), __entry->name, + pipe_name(__entry->pipe), __get_str(name), __entry->frame, __entry->scanline, DRM_RECT_FP_ARG((const struct drm_rect *)__entry->src), DRM_RECT_ARG((const struct drm_rect *)__entry->dst)) @@ -328,21 +328,21 @@ TRACE_EVENT(intel_disable_plane, TP_STRUCT__entry( __field(enum pipe, pipe) - __field(const char *, name) __field(u32, frame) __field(u32, scanline) + __string(name, plane->name) ), TP_fast_assign( + __assign_str(name, plane->name); __entry->pipe = crtc->pipe; - __entry->name = plane->name; __entry->frame = crtc->base.dev->driver->get_vblank_counter(crtc->base.dev, crtc->pipe); __entry->scanline = intel_get_crtc_scanline(crtc); ), TP_printk("pipe %c, plane %s, frame=%u, scanline=%u", - pipe_name(__entry->pipe), __entry->name, + pipe_name(__entry->pipe), __get_str(name), __entry->frame, __entry->scanline) ); -- 2.20.1