From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C010B2512DE; Tue, 20 May 2025 14:13:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747750427; cv=none; b=SkBLCwTgnYqc5212kraxoNWtKMfgseGtdqfVs3dGsdKBIa4nZPD6UmHLn3MWQifRgsMWXSPv4FuI4HOJXK0LcIz4IHIGFFasAQj/+rCaaepAV4gT6u3cagnBbPbHinMauvXFwURjK09Y2gIRjGZGWwRogzWW4ngjiRhrzEoweuI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747750427; c=relaxed/simple; bh=ztOSff1Or/4NVXvuikm36NkizQWPh5H86+om5yHJwwI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sH7H7FmI//8jStzXNfDSUUY5UEdXd5/GN8LoNQbbRPMha+YveZ+n351bBAd5wPNNmxtPJdh2LbNHggTNp5A06Rk7/CEzAsLPY/kkLls/XNTzYyze1VAPSAlEnrFQ7wqkoakyGHVSEMuLnCJafHbXBAHpEB7zDu+Tg9Q3ibm8oW4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=G7u6PGQJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="G7u6PGQJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1984C4CEE9; Tue, 20 May 2025 14:13:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1747750427; bh=ztOSff1Or/4NVXvuikm36NkizQWPh5H86+om5yHJwwI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G7u6PGQJtZgyadY2ZM6S/3C6nI8AkPmup1ROwDR2AEb6PrrHc+g8ONnUwG9e9qHCh lexP48Esxx0NFl4drxfkni4VtQcZz9JKCUsodGoUXbje0CEEOXjwH9etaEyFmnYFO+ EeZXLCZ7ahZQcj5wGW5BLyPaQgV8Qd7MB4xP9DLk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable , Andrei Kuchynski , Heikki Krogerus Subject: [PATCH 6.12 141/143] usb: typec: ucsi: displayport: Fix deadlock Date: Tue, 20 May 2025 15:51:36 +0200 Message-ID: <20250520125815.557845626@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250520125810.036375422@linuxfoundation.org> References: <20250520125810.036375422@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrei Kuchynski commit 364618c89d4c57c85e5fc51a2446cd939bf57802 upstream. This patch introduces the ucsi_con_mutex_lock / ucsi_con_mutex_unlock functions to the UCSI driver. ucsi_con_mutex_lock ensures the connector mutex is only locked if a connection is established and the partner pointer is valid. This resolves a deadlock scenario where ucsi_displayport_remove_partner holds con->mutex waiting for dp_altmode_work to complete while dp_altmode_work attempts to acquire it. Cc: stable Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode") Signed-off-by: Andrei Kuchynski Reviewed-by: Heikki Krogerus Link: https://lore.kernel.org/r/20250424084429.3220757-2-akuchynski@chromium.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/ucsi/displayport.c | 19 +++++++++++-------- drivers/usb/typec/ucsi/ucsi.c | 34 ++++++++++++++++++++++++++++++++++ drivers/usb/typec/ucsi/ucsi.h | 2 ++ 3 files changed, 47 insertions(+), 8 deletions(-) --- a/drivers/usb/typec/ucsi/displayport.c +++ b/drivers/usb/typec/ucsi/displayport.c @@ -54,7 +54,8 @@ static int ucsi_displayport_enter(struct u8 cur = 0; int ret; - mutex_lock(&dp->con->lock); + if (!ucsi_con_mutex_lock(dp->con)) + return -ENOTCONN; if (!dp->override && dp->initialized) { const struct typec_altmode *p = typec_altmode_get_partner(alt); @@ -100,7 +101,7 @@ static int ucsi_displayport_enter(struct schedule_work(&dp->work); ret = 0; err_unlock: - mutex_unlock(&dp->con->lock); + ucsi_con_mutex_unlock(dp->con); return ret; } @@ -112,7 +113,8 @@ static int ucsi_displayport_exit(struct u64 command; int ret = 0; - mutex_lock(&dp->con->lock); + if (!ucsi_con_mutex_lock(dp->con)) + return -ENOTCONN; if (!dp->override) { const struct typec_altmode *p = typec_altmode_get_partner(alt); @@ -144,7 +146,7 @@ static int ucsi_displayport_exit(struct schedule_work(&dp->work); out_unlock: - mutex_unlock(&dp->con->lock); + ucsi_con_mutex_unlock(dp->con); return ret; } @@ -202,20 +204,21 @@ static int ucsi_displayport_vdm(struct t int cmd = PD_VDO_CMD(header); int svdm_version; - mutex_lock(&dp->con->lock); + if (!ucsi_con_mutex_lock(dp->con)) + return -ENOTCONN; if (!dp->override && dp->initialized) { const struct typec_altmode *p = typec_altmode_get_partner(alt); dev_warn(&p->dev, "firmware doesn't support alternate mode overriding\n"); - mutex_unlock(&dp->con->lock); + ucsi_con_mutex_unlock(dp->con); return -EOPNOTSUPP; } svdm_version = typec_altmode_get_svdm_version(alt); if (svdm_version < 0) { - mutex_unlock(&dp->con->lock); + ucsi_con_mutex_unlock(dp->con); return svdm_version; } @@ -259,7 +262,7 @@ static int ucsi_displayport_vdm(struct t break; } - mutex_unlock(&dp->con->lock); + ucsi_con_mutex_unlock(dp->con); return 0; } --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -1904,6 +1904,40 @@ void ucsi_set_drvdata(struct ucsi *ucsi, EXPORT_SYMBOL_GPL(ucsi_set_drvdata); /** + * ucsi_con_mutex_lock - Acquire the connector mutex + * @con: The connector interface to lock + * + * Returns true on success, false if the connector is disconnected + */ +bool ucsi_con_mutex_lock(struct ucsi_connector *con) +{ + bool mutex_locked = false; + bool connected = true; + + while (connected && !mutex_locked) { + mutex_locked = mutex_trylock(&con->lock) != 0; + connected = con->status.flags & UCSI_CONSTAT_CONNECTED; + if (connected && !mutex_locked) + msleep(20); + } + + connected = connected && con->partner; + if (!connected && mutex_locked) + mutex_unlock(&con->lock); + + return connected; +} + +/** + * ucsi_con_mutex_unlock - Release the connector mutex + * @con: The connector interface to unlock + */ +void ucsi_con_mutex_unlock(struct ucsi_connector *con) +{ + mutex_unlock(&con->lock); +} + +/** * ucsi_create - Allocate UCSI instance * @dev: Device interface to the PPM (Platform Policy Manager) * @ops: I/O routines --- a/drivers/usb/typec/ucsi/ucsi.h +++ b/drivers/usb/typec/ucsi/ucsi.h @@ -91,6 +91,8 @@ int ucsi_register(struct ucsi *ucsi); void ucsi_unregister(struct ucsi *ucsi); void *ucsi_get_drvdata(struct ucsi *ucsi); void ucsi_set_drvdata(struct ucsi *ucsi, void *data); +bool ucsi_con_mutex_lock(struct ucsi_connector *con); +void ucsi_con_mutex_unlock(struct ucsi_connector *con); void ucsi_connector_change(struct ucsi *ucsi, u8 num);