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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61DEDC433E6 for ; Tue, 1 Sep 2020 15:49:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EC1F2064B for ; Tue, 1 Sep 2020 15:49:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598975390; bh=xfO1u2PPaS2QW8600aN9UjDU60PC4B7Dyb/0Idw7mcU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uDdeORjC4JIdkddPRAO3QOFVRpZ02yLxfjnimNXsKxQEY0YqqwgNgX7fEB7esCaOW SfXJca6wHRSdslaiaCQBE8bMRJI5L3G6tiQyZU96eM9rbXGUFyDVexoaQPkkRs3WIx Izl7+7TjrUGABpQJ3Le/Kor/roux7odVGRFS9+T4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732138AbgIAPtq (ORCPT ); Tue, 1 Sep 2020 11:49:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:35788 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731694AbgIAPqQ (ORCPT ); Tue, 1 Sep 2020 11:46:16 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 CB4D6206FA; Tue, 1 Sep 2020 15:46:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598975175; bh=xfO1u2PPaS2QW8600aN9UjDU60PC4B7Dyb/0Idw7mcU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iz1uZuC3OGqsff6teGrZhQrY6ya63R7+sJk5TKx18qRfXjdrA8rh98LDugQOV0fgL 7rotVEB5TeaC2lJCh/DSNV7+HDZhFqwK6wk4OWKviGJbeEfY0qcnjtyGeuLi+t05G4 pSGjc8mZW7Ocd8zQ49IzEr3lXjLO/OqRMcQH4TdM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hans de Goede , Heikki Krogerus , Guenter Roeck Subject: [PATCH 5.8 238/255] usb: typec: ucsi: Fix AB BA lock inversion Date: Tue, 1 Sep 2020 17:11:34 +0200 Message-Id: <20200901151012.158111855@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901151000.800754757@linuxfoundation.org> References: <20200901151000.800754757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hans de Goede commit 0ff0705a2ef2929e9326c95df48bdbebb0dafaad upstream. 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 Acked-by: Heikki Krogerus Reviewed-by: Guenter Roeck Link: https://lore.kernel.org/r/20200809141904.4317-2-hdegoede@redhat.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/ucsi/ucsi.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -205,7 +205,7 @@ void ucsi_altmode_update_active(struct u 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 ucs 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 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 ucs /* 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 ucs /* 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 @@ err_unregister: con->port = NULL; } + mutex_lock(&ucsi->ppm_lock); err_reset: ucsi_reset_ppm(ucsi); err: