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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77DBFC433EF for ; Mon, 1 Nov 2021 09:46:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AD5860F24 for ; Mon, 1 Nov 2021 09:46:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234443AbhKAJsU (ORCPT ); Mon, 1 Nov 2021 05:48:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:47952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234072AbhKAJoD (ORCPT ); Mon, 1 Nov 2021 05:44:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 519DC613A7; Mon, 1 Nov 2021 09:29:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1635758963; bh=xVN+tuD72jEaxUbrrSNkVumd7VGK1bDnzJPn6ufC6Ng=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=at7aOPxtj90FCH6v3XlgfucvaIzYjg11A8P3c3SwFqJb+odmTyInQoscjqKF1L+JX 5Ym4HOV0NBywcJvxBc0eQz2la/wclN5e+2c3MpizHBf+/ktnIbBx0nMBueaezMadOJ 0jNsvq2bH7+xfDuolJi92i6Yrys7+IVzMmJ6Ia48= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nicholas Kazlauskas , Aric Cyr , Alex Deucher Subject: [PATCH 5.14 056/125] drm/amd/display: Fix deadlock when falling back to v2 from v3 Date: Mon, 1 Nov 2021 10:17:09 +0100 Message-Id: <20211101082543.773829070@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211101082533.618411490@linuxfoundation.org> References: <20211101082533.618411490@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nicholas Kazlauskas commit ad76744b041d8c87ef1c9adbb04fb7eaa20a179e upstream. [Why] A deadlock in the kernel occurs when we fallback from the V3 to V2 add_topology_to_display or remove_topology_to_display because they both try to acquire the dtm_mutex but recursive locking isn't supported on mutex_lock(). [How] Make the mutex_lock/unlock more fine grained and move them up such that they're only required for the psp invocation itself. Fixes: bf62221e9d0e ("drm/amd/display: Add DCN3.1 HDCP support") Signed-off-by: Nicholas Kazlauskas Reviewed-by: Aric Cyr Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c +++ b/drivers/gpu/drm/amd/display/modules/hdcp/hdcp_psp.c @@ -105,6 +105,7 @@ static enum mod_hdcp_status mod_hdcp_rem dtm_cmd->dtm_status = TA_DTM_STATUS__GENERIC_FAILURE; psp_dtm_invoke(psp, dtm_cmd->cmd_id); + mutex_unlock(&psp->dtm_context.mutex); if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) { status = mod_hdcp_remove_display_from_topology_v2(hdcp, index); @@ -115,8 +116,6 @@ static enum mod_hdcp_status mod_hdcp_rem HDCP_TOP_REMOVE_DISPLAY_TRACE(hdcp, display->index); } - mutex_unlock(&psp->dtm_context.mutex); - return status; } @@ -218,6 +217,7 @@ static enum mod_hdcp_status mod_hdcp_add dtm_cmd->dtm_in_message.topology_update_v3.link_hdcp_cap = link->hdcp_supported_informational; psp_dtm_invoke(psp, dtm_cmd->cmd_id); + mutex_unlock(&psp->dtm_context.mutex); if (dtm_cmd->dtm_status != TA_DTM_STATUS__SUCCESS) { status = mod_hdcp_add_display_to_topology_v2(hdcp, display); @@ -227,8 +227,6 @@ static enum mod_hdcp_status mod_hdcp_add HDCP_TOP_ADD_DISPLAY_TRACE(hdcp, display->index); } - mutex_unlock(&psp->dtm_context.mutex); - return status; }