From patchwork Wed Jul 10 16:01:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 11038721 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C4A0814F6 for ; Wed, 10 Jul 2019 16:01:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B808D28922 for ; Wed, 10 Jul 2019 16:01:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ACDF128974; Wed, 10 Jul 2019 16:01:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 55CCF28922 for ; Wed, 10 Jul 2019 16:01:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0D06D6E110; Wed, 10 Jul 2019 16:01:13 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 16AE76E10F; Wed, 10 Jul 2019 16:01:12 +0000 (UTC) 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 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 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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) );