From patchwork Sun Aug 9 14:19:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 11706717 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 13E0A138C for ; Sun, 9 Aug 2020 14:19:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAB05206B6 for ; Sun, 9 Aug 2020 14:19:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="JNEgyU1w" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726370AbgHIOTT (ORCPT ); Sun, 9 Aug 2020 10:19:19 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:25610 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726293AbgHIOTR (ORCPT ); Sun, 9 Aug 2020 10:19:17 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1596982753; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3SxBwwd/jGFDYXHUnTvTxkgkCOmK+BmPZI0Qya15sKI=; b=JNEgyU1w0to7yBXD2OXCrG1vUnlaaDlT5zKjPKdJwtX+jQSQhuhOBNZn3fE3nj40HcNFx7 W5XKmRV26kpSYoO0B/2YfIsdxUeKZ04k5aCZ9nS4MSnWidKqr1nQKJGRGdwGRLz9gRxqUG 77wH7qmoehaCAfwckD29D5xP3gl4KSs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-232-rbjyxjQ3NQi0B5g-dDpI3g-1; Sun, 09 Aug 2020 10:19:09 -0400 X-MC-Unique: rbjyxjQ3NQi0B5g-dDpI3g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9EBB457; Sun, 9 Aug 2020 14:19:08 +0000 (UTC) Received: from x1.localdomain.com (ovpn-112-24.ams2.redhat.com [10.36.112.24]) by smtp.corp.redhat.com (Postfix) with ESMTP id 67A8989528; Sun, 9 Aug 2020 14:19:07 +0000 (UTC) From: Hans de Goede To: Greg Kroah-Hartman , Guenter Roeck , Heikki Krogerus Cc: Hans de Goede , linux-usb@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/4] usb: typec: ucsi: Fix AB BA lock inversion Date: Sun, 9 Aug 2020 16:19:01 +0200 Message-Id: <20200809141904.4317-2-hdegoede@redhat.com> In-Reply-To: <20200809141904.4317-1-hdegoede@redhat.com> References: <20200809141904.4317-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Lockdep reports an AB BA lock inversion between ucsi_init() and ucsi_handle_connector_change(): AB order: 1. ucsi_init takes ucsi->ppm_lock (it runs with that locked for the duration of the function) 2. usci_init eventually end up calling ucsi_register_displayport, which takes ucsi_connector->lock BA order: 1. ucsi_handle_connector_change work is started, takes ucsi_connector->lock 2. ucsi_handle_connector_change calls ucsi_send_command which takes ucsi->ppm_lock The ppm_lock really only needs to be hold during 2 functions: ucsi_reset_ppm() and ucsi_run_command(). This commit fixes the AB BA lock inversion by making ucsi_init drop the ucsi->ppm_lock before it starts registering ports; and replacing any ucsi_run_command() calls after this point with ucsi_send_command() (which is a wrapper around run_command taking the lock while handling the command). Some of the replacing of ucsi_run_command with ucsi_send_command in the helpers used during port registration also fixes a number of code paths after registration which call ucsi_run_command() without holding the ppm_lock: 1. ucsi_altmode_update_active() call in ucsi/displayport.c 2. ucsi_register_altmodes() call from ucsi_handle_connector_change() (through ucsi_partner_change()) Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede --- drivers/usb/typec/ucsi/ucsi.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index d0c63afaf345..d9d93f83b2a6 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -205,7 +205,7 @@ void ucsi_altmode_update_active(struct ucsi_connector *con) int i; command = UCSI_GET_CURRENT_CAM | UCSI_CONNECTOR_NUMBER(con->num); - ret = ucsi_run_command(con->ucsi, command, &cur, sizeof(cur)); + ret = ucsi_send_command(con->ucsi, command, &cur, sizeof(cur)); if (ret < 0) { if (con->ucsi->version > 0x0100) { dev_err(con->ucsi->dev, @@ -354,7 +354,7 @@ ucsi_register_altmodes_nvidia(struct ucsi_connector *con, u8 recipient) command |= UCSI_GET_ALTMODE_RECIPIENT(recipient); command |= UCSI_GET_ALTMODE_CONNECTOR_NUMBER(con->num); command |= UCSI_GET_ALTMODE_OFFSET(i); - len = ucsi_run_command(con->ucsi, command, &alt, sizeof(alt)); + len = ucsi_send_command(con->ucsi, command, &alt, sizeof(alt)); /* * We are collecting all altmodes first and then registering. * Some type-C device will return zero length data beyond last @@ -431,7 +431,7 @@ static int ucsi_register_altmodes(struct ucsi_connector *con, u8 recipient) command |= UCSI_GET_ALTMODE_RECIPIENT(recipient); command |= UCSI_GET_ALTMODE_CONNECTOR_NUMBER(con->num); command |= UCSI_GET_ALTMODE_OFFSET(i); - len = ucsi_run_command(con->ucsi, command, alt, sizeof(alt)); + len = ucsi_send_command(con->ucsi, command, alt, sizeof(alt)); if (len <= 0) return len; @@ -904,7 +904,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) /* Get connector capability */ command = UCSI_GET_CONNECTOR_CAPABILITY; command |= UCSI_CONNECTOR_NUMBER(con->num); - ret = ucsi_run_command(ucsi, command, &con->cap, sizeof(con->cap)); + ret = ucsi_send_command(ucsi, command, &con->cap, sizeof(con->cap)); if (ret < 0) return ret; @@ -953,8 +953,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) /* Get the status */ command = UCSI_GET_CONNECTOR_STATUS | UCSI_CONNECTOR_NUMBER(con->num); - ret = ucsi_run_command(ucsi, command, &con->status, - sizeof(con->status)); + ret = ucsi_send_command(ucsi, command, &con->status, sizeof(con->status)); if (ret < 0) { dev_err(ucsi->dev, "con%d: failed to get status\n", con->num); return 0; @@ -1044,6 +1043,8 @@ int ucsi_init(struct ucsi *ucsi) goto err_reset; } + mutex_unlock(&ucsi->ppm_lock); + /* Register all connectors */ for (i = 0; i < ucsi->cap.num_connectors; i++) { ret = ucsi_register_port(ucsi, i); @@ -1054,12 +1055,10 @@ int ucsi_init(struct ucsi *ucsi) /* Enable all notifications */ ucsi->ntfy = UCSI_ENABLE_NTFY_ALL; command = UCSI_SET_NOTIFICATION_ENABLE | ucsi->ntfy; - ret = ucsi_run_command(ucsi, command, NULL, 0); + ret = ucsi_send_command(ucsi, command, NULL, 0); if (ret < 0) goto err_unregister; - mutex_unlock(&ucsi->ppm_lock); - return 0; err_unregister: @@ -1071,6 +1070,7 @@ int ucsi_init(struct ucsi *ucsi) con->port = NULL; } + mutex_lock(&ucsi->ppm_lock); err_reset: ucsi_reset_ppm(ucsi); err: