From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DCDBA23CE for ; Tue, 3 Dec 2024 16:01:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733241714; cv=none; b=OoSm3UTfLAo2oH1CcOT0ImAp9mP4LTwOC3OqhuErfE7PClGk0Ce1fDUM6f9ekFBDVXIW+ZbtX5DcWPKhrFOy4F6ClHOrTC0R39c9gXjlBu1HiE7DNOu73bLCJnvrZj/W45EP61DBexhH+ghnKRIw4NOzH55px0FobkFkhm0GlWI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733241714; c=relaxed/simple; bh=AmnQe6A3KxtcW8XP/QhfkCqFZwG4vY1KZmdy7VCDCSE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pT5PgBXQ0l1daNtaEDtm86NnPfvizocAcWinvgkxWISI5tnP8myXSmYmt6u3mKbECKFH+4LwaCdjhJkAthUMYOZ7Yu1XSL+A9JLXuSq4YsH3Pqc5gklkQohMckO50VrgLDNbf90phb6isJcnuDAzwc7jrATG2e15X1eFsQvBPnM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Y7kKacuK; arc=none smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Y7kKacuK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1733241711; x=1764777711; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=AmnQe6A3KxtcW8XP/QhfkCqFZwG4vY1KZmdy7VCDCSE=; b=Y7kKacuKVwmT220iSP3YrcqxipeKSYKTXQ4cSOHFZgJmkRWrWOqkhoxs VxG3lDtGsfR0cU4Lowf4xSnzQf9mMWKag04KXD+5jvPp+3dOOeYDbcRLw MC1j/1fu59oL/ichtNKqKufAiWCirXgkNNn55EIiklUfqY8/EKw3po+KJ eRptjeqHcoZd/F8pmPfwlWcUS1PprOwfVeUF52aqU/fPnf7r888hJg7yM s0rJkgAyULAyRWEw2ELnMkiif+xGn+mlzf2c1l35equZgDquqt5PmwTND F/elq39dmgXFwBJCzoI4G4wzw8zj6Gv+NaXwQAc1+404mlGroiB1dAaM/ A==; X-CSE-ConnectionGUID: eJ3e0xXsTwiET4Xy5Ugw8w== X-CSE-MsgGUID: mWq7YydxRkKKp1e2zztj7Q== X-IronPort-AV: E=McAfee;i="6700,10204,11275"; a="37236043" X-IronPort-AV: E=Sophos;i="6.12,205,1728975600"; d="scan'208";a="37236043" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Dec 2024 08:01:51 -0800 X-CSE-ConnectionGUID: 5NXC7kwaRM6M5bMoCnsxVg== X-CSE-MsgGUID: kNJWxcxaSvalCDKednLhpw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,205,1728975600"; d="scan'208";a="93313031" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Dec 2024 08:01:45 -0800 From: Imre Deak To: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org, Lyude Paul , stable@vger.kernel.org Subject: [PATCH 1/7] drm/dp_mst: Fix resetting msg rx state after topology removal Date: Tue, 3 Dec 2024 18:02:17 +0200 Message-ID: <20241203160223.2926014-2-imre.deak@intel.com> X-Mailer: git-send-email 2.44.2 In-Reply-To: <20241203160223.2926014-1-imre.deak@intel.com> References: <20241203160223.2926014-1-imre.deak@intel.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit If the MST topology is removed during the reception of an MST down reply or MST up request sideband message, the drm_dp_mst_topology_mgr::up_req_recv/down_rep_recv states could be reset from one thread via drm_dp_mst_topology_mgr_set_mst(false), racing with the reading/parsing of the message from another thread via drm_dp_mst_handle_down_rep() or drm_dp_mst_handle_up_req(). The race is possible since the reader/parser doesn't hold any lock while accessing the reception state. This in turn can lead to a memory corruption in the reader/parser as described by commit bd2fccac61b4 ("drm/dp_mst: Fix MST sideband message body length check"). Fix the above by resetting the message reception state if needed before reading/parsing a message. Another solution would be to hold the drm_dp_mst_topology_mgr::lock for the whole duration of the message reception/parsing in drm_dp_mst_handle_down_rep() and drm_dp_mst_handle_up_req(), however this would require a bigger change. Since the fix is also needed for stable, opting for the simpler solution in this patch. Cc: Lyude Paul Cc: Fixes: 1d082618bbf3 ("drm/display/dp_mst: Fix down/up message handling after sink disconnect") Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13056 Signed-off-by: Imre Deak --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 21 +++++++++++++++++-- include/drm/display/drm_dp_mst_helper.h | 7 +++++++ 2 files changed, 26 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index e6ee180815b20..1475aa95ab6b2 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -3700,8 +3700,7 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms ret = 0; mgr->payload_id_table_cleared = false; - memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv)); - memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv)); + mgr->reset_rx_state = true; } out_unlock: @@ -3859,6 +3858,11 @@ int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr, } EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume); +static void reset_msg_rx_state(struct drm_dp_sideband_msg_rx *msg) +{ + memset(msg, 0, sizeof(*msg)); +} + static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up, struct drm_dp_mst_branch **mstb) @@ -4141,6 +4145,17 @@ static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr) return 0; } +static void update_msg_rx_state(struct drm_dp_mst_topology_mgr *mgr) +{ + mutex_lock(&mgr->lock); + if (mgr->reset_rx_state) { + mgr->reset_rx_state = false; + reset_msg_rx_state(&mgr->down_rep_recv); + reset_msg_rx_state(&mgr->up_req_recv); + } + mutex_unlock(&mgr->lock); +} + /** * drm_dp_mst_hpd_irq_handle_event() - MST hotplug IRQ handle MST event * @mgr: manager to notify irq for. @@ -4175,6 +4190,8 @@ int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u *handled = true; } + update_msg_rx_state(mgr); + if (esi[1] & DP_DOWN_REP_MSG_RDY) { ret = drm_dp_mst_handle_down_rep(mgr); *handled = true; diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h index f6a1cbb0f600f..a80ba457a858f 100644 --- a/include/drm/display/drm_dp_mst_helper.h +++ b/include/drm/display/drm_dp_mst_helper.h @@ -699,6 +699,13 @@ struct drm_dp_mst_topology_mgr { */ bool payload_id_table_cleared : 1; + /** + * @reset_rx_state: The down request's reply and up request message + * receiver state must be reset, after the topology manager got + * removed. Protected by @lock. + */ + bool reset_rx_state : 1; + /** * @payload_count: The number of currently active payloads in hardware. This value is only * intended to be used internally by MST helpers for payload tracking, and is only safe to -- 2.44.2