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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CA49CCCA47C for ; Tue, 7 Jun 2022 18:28:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351048AbiFGS23 (ORCPT ); Tue, 7 Jun 2022 14:28:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351639AbiFGSQe (ORCPT ); Tue, 7 Jun 2022 14:16:34 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DB861668B1; Tue, 7 Jun 2022 10:49:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 18EA3B82340; Tue, 7 Jun 2022 17:49:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77A9AC385A5; Tue, 7 Jun 2022 17:49:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624186; bh=jCgpnnoSkDT54evi1luL+K6mgNflbygqRCA4lF4dyvI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BhtoUAXG3nImu3KnPpsY7vapoDpJ/2Bmsyli5HK3oI/EDkdm0Yv7bFjTojdv1W9Ao 8DsB1juM9G9NIzuOYn4mYQYoFPrrgkAZ4KaKUeOe5kuV23zNCpnoBY490zXQd1mRgT znKja4FXYo0+e8i++QxVhksS8y7IlIzLnotNKxQtjVKjb0KQ1eLAJ7VWZe5xbEovFX We2RK4WbeIo6akkKi0DESVrvtMZOdeJzJURLk9BQSjynl6lgl26RjDGsvRZaqN4lCe 3na2vmKjht4UxFZAQPnIW4+29jzUp3oIET/VApt50LHZD3sJ3MQIccD0D53sHHoS/u nSvqe8ysfb6aw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Duoming Zhou , Greg Kroah-Hartman , Sasha Levin , Larry.Finger@lwfinger.net, phil@philpotter.co.uk, straube.linux@gmail.com, martin@kaiser.cx, jhpark1013@gmail.com, linux-staging@lists.linux.dev Subject: [PATCH AUTOSEL 5.18 07/68] drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle Date: Tue, 7 Jun 2022 13:47:33 -0400 Message-Id: <20220607174846.477972-7-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607174846.477972-1-sashal@kernel.org> References: <20220607174846.477972-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Duoming Zhou [ Upstream commit 0fcddf9c7c10202946d5b19409efbdff744fba88 ] There is a deadlock in rtw_joinbss_event_prehandle(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_joinbss_event_prehandle()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | rtw_join_timeout_handler() | _rtw_join_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_joinbss_event_prehandle() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() to spin_lock_irq() in _rtw_join_timeout_handler() in order to prevent deadlock. Signed-off-by: Duoming Zhou Link: https://lore.kernel.org/r/20220409072135.74248-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/staging/r8188eu/core/rtw_mlme.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c index 6f0bff186477..76cf6a69bf0f 100644 --- a/drivers/staging/r8188eu/core/rtw_mlme.c +++ b/drivers/staging/r8188eu/core/rtw_mlme.c @@ -1071,8 +1071,10 @@ void rtw_joinbss_event_prehandle(struct adapter *adapter, u8 *pbuf) rtw_indicate_connect(adapter); } + spin_unlock_bh(&pmlmepriv->lock); /* s5. Cancel assoc_timer */ del_timer_sync(&pmlmepriv->assoc_timer); + spin_lock_bh(&pmlmepriv->lock); } else { spin_unlock_bh(&pmlmepriv->scanned_queue.lock); goto ignore_joinbss_callback; @@ -1310,7 +1312,7 @@ void _rtw_join_timeout_handler (struct adapter *adapter) if (adapter->bDriverStopped || adapter->bSurpriseRemoved) return; - spin_lock_bh(&pmlmepriv->lock); + spin_lock_irq(&pmlmepriv->lock); if (rtw_to_roaming(adapter) > 0) { /* join timeout caused by roaming */ while (1) { @@ -1329,7 +1331,7 @@ void _rtw_join_timeout_handler (struct adapter *adapter) rtw_indicate_disconnect(adapter); free_scanqueue(pmlmepriv);/* */ } - spin_unlock_bh(&pmlmepriv->lock); + spin_unlock_irq(&pmlmepriv->lock); } -- 2.35.1