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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 60CB3E7718A for ; Fri, 20 Dec 2024 09:12:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 23AF610E384; Fri, 20 Dec 2024 09:12:02 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="WC4JmkZt"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.11]) by gabe.freedesktop.org (Postfix) with ESMTPS id 115E110E384; Fri, 20 Dec 2024 09:12:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1734685921; x=1766221921; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=Y6fWIpNpn6+RfkCwXAYImqJKK8WJMBpzJdscsLxngmk=; b=WC4JmkZtrdWO+mQsgKUrJ9DGK+dlQvI7AJs2pSqPsY1Z72DmWDqt4nmF +FNOqNlF+f0ami9cuIXYYtKXzA9LX1nM8OSU023JkMkEPQiJ2WBmqGl3Q 77K+D3MeCd835x/jluNlMN2gxHjkg+tOC29DoGt7jhTne/tWtdS45f87h 9jGV2i04ZCSjyLlucfpkopEOTE82ZyVncPyDxXmAx4+nUH7FvuREF8b6I AVjXnhbHCHwxlWi+N0HVDe9Se4VehW5Z4zoMAKyu4SGLZ43gWCEiWULyv TapG6+eURl/c2x7Yhkzry6Eq7W5FropiyTdK261+SCnzgcX1pFQM/SvAH w==; X-CSE-ConnectionGUID: R1zxceReQ7CJQVr7U2oukA== X-CSE-MsgGUID: zcSvNclCRFStBcsinMk1fg== X-IronPort-AV: E=McAfee;i="6700,10204,11291"; a="45834874" X-IronPort-AV: E=Sophos;i="6.12,250,1728975600"; d="scan'208";a="45834874" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by fmvoesa105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Dec 2024 01:12:00 -0800 X-CSE-ConnectionGUID: VokFSDUPT0ucR0XQoYSd1A== X-CSE-MsgGUID: y5XR78syS+KOFb/33K20qw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,250,1728975600"; d="scan'208";a="98659126" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.74]) by fmviesa008.fm.intel.com with SMTP; 20 Dec 2024 01:11:58 -0800 Received: by stinkbox (sSMTP sendmail emulation); Fri, 20 Dec 2024 11:11:57 +0200 Date: Fri, 20 Dec 2024 11:11:57 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Gustavo Sousa Cc: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Jani Nikula Subject: Re: [PATCH 1/3] drm/i915/display: Do not assume zero offset when duplicating global state Message-ID: References: <20241219214909.104869-1-gustavo.sousa@intel.com> <20241219214909.104869-2-gustavo.sousa@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241219214909.104869-2-gustavo.sousa@intel.com> X-Patchwork-Hint: comment X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Thu, Dec 19, 2024 at 06:48:36PM -0300, Gustavo Sousa wrote: > The current intel_*_duplicate_state() functions assume the offset for > the base member of their state structures is zero when calling > kmemdup(). While that is true today, such assumption should not be made > and proper offset must be applied when calling kmemdup(), otherwise we > will be duplicating the wrong memory area if, for some reason, the > offset is changed in the future. All kms objects we use make that same assumption. I think the correct thing to do is to just throw in some BUILD_BUG_ON()/etc. to make the thing not build if that doesn't hold. I had a patch like that ages ago, but it's no doubt 110% stale by now. I suppose no real harm if avoiding that assumption in spots like this, but the &foo->base==NULL <-> foo==NULL assumptions we have all over the place are the far bigger issue. > > As such, update each of those functions to use its respective > to_*_state() as the parameter to kmemdup(). > > Signed-off-by: Gustavo Sousa > --- > drivers/gpu/drm/i915/display/intel_bw.c | 4 ++-- > drivers/gpu/drm/i915/display/intel_cdclk.c | 4 ++-- > drivers/gpu/drm/i915/display/intel_pmdemand.c | 4 ++-- > drivers/gpu/drm/i915/display/skl_watermark.c | 4 ++-- > 4 files changed, 8 insertions(+), 8 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c > index 08e8a67ca74c..30236010e0ed 100644 > --- a/drivers/gpu/drm/i915/display/intel_bw.c > +++ b/drivers/gpu/drm/i915/display/intel_bw.c > @@ -1425,9 +1425,9 @@ int intel_bw_atomic_check(struct intel_atomic_state *state) > static struct intel_global_state * > intel_bw_duplicate_state(struct intel_global_obj *obj) > { > - struct intel_bw_state *state; > + struct intel_bw_state *state = to_intel_bw_state(obj->state); > > - state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL); > + state = kmemdup(state, sizeof(*state), GFP_KERNEL); > if (!state) > return NULL; > > diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c > index 3506e576bf6b..fc084e2a4c6a 100644 > --- a/drivers/gpu/drm/i915/display/intel_cdclk.c > +++ b/drivers/gpu/drm/i915/display/intel_cdclk.c > @@ -3130,9 +3130,9 @@ static int fixed_modeset_calc_cdclk(struct intel_atomic_state *state) > > static struct intel_global_state *intel_cdclk_duplicate_state(struct intel_global_obj *obj) > { > - struct intel_cdclk_state *cdclk_state; > + struct intel_cdclk_state *cdclk_state = to_intel_cdclk_state(obj->state); > > - cdclk_state = kmemdup(obj->state, sizeof(*cdclk_state), GFP_KERNEL); > + cdclk_state = kmemdup(cdclk_state, sizeof(*cdclk_state), GFP_KERNEL); > if (!cdclk_state) > return NULL; > > diff --git a/drivers/gpu/drm/i915/display/intel_pmdemand.c b/drivers/gpu/drm/i915/display/intel_pmdemand.c > index cdd314956a31..1f71efb7d04d 100644 > --- a/drivers/gpu/drm/i915/display/intel_pmdemand.c > +++ b/drivers/gpu/drm/i915/display/intel_pmdemand.c > @@ -18,9 +18,9 @@ > static struct intel_global_state * > intel_pmdemand_duplicate_state(struct intel_global_obj *obj) > { > - struct intel_pmdemand_state *pmdemand_state; > + struct intel_pmdemand_state *pmdemand_state = to_intel_pmdemand_state(obj->state); > > - pmdemand_state = kmemdup(obj->state, sizeof(*pmdemand_state), GFP_KERNEL); > + pmdemand_state = kmemdup(pmdemand_state, sizeof(*pmdemand_state), GFP_KERNEL); > if (!pmdemand_state) > return NULL; > > diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c b/drivers/gpu/drm/i915/display/skl_watermark.c > index 29e8ea91c858..b3d38e09df5a 100644 > --- a/drivers/gpu/drm/i915/display/skl_watermark.c > +++ b/drivers/gpu/drm/i915/display/skl_watermark.c > @@ -3291,9 +3291,9 @@ static void skl_setup_wm_latency(struct drm_i915_private *i915) > > static struct intel_global_state *intel_dbuf_duplicate_state(struct intel_global_obj *obj) > { > - struct intel_dbuf_state *dbuf_state; > + struct intel_dbuf_state *dbuf_state = to_intel_dbuf_state(obj->state); > > - dbuf_state = kmemdup(obj->state, sizeof(*dbuf_state), GFP_KERNEL); > + dbuf_state = kmemdup(dbuf_state, sizeof(*dbuf_state), GFP_KERNEL); > if (!dbuf_state) > return NULL; > > -- > 2.47.1 -- Ville Syrjälä Intel