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 C6C04CCA480 for ; Mon, 13 Jun 2022 13:20:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376497AbiFMNTA (ORCPT ); Mon, 13 Jun 2022 09:19:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39066 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359490AbiFMNJ6 (ORCPT ); Mon, 13 Jun 2022 09:09:58 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6072F3A1AB; Mon, 13 Jun 2022 04:20:59 -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 EAC35B80D3A; Mon, 13 Jun 2022 11:20:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5436FC34114; Mon, 13 Jun 2022 11:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655119256; bh=UZ5Dc/FfKOsM7z4voa90CsZSNexUen7lsXLITcFOEA0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OHm6Jz7ZBPj0lBT5i7taaK8dTi6QL5E508dQpc0hzZOd/xf1HifYAI0OGpSksq8/c imM6BUYQ5iUaXdFxJ3V7UkM8uqiq1Nspx3K2zhuX2iqJvYLOhBj5pJp0zhZVVI4hT/ eHjiH7crnlE/t44BkVikS2vycr/FjT4O40TOR0Ik= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Duoming Zhou , Sasha Levin Subject: [PATCH 5.15 169/247] drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback() Date: Mon, 13 Jun 2022 12:11:11 +0200 Message-Id: <20220613094928.083747391@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094922.843438024@linuxfoundation.org> References: <20220613094922.843438024@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: Duoming Zhou [ Upstream commit cc7ad0d77b51c872d629bcd98aea463a3c4109e7 ] There is a deadlock in rtw_surveydone_event_callback(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_surveydone_event_callback()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | rtw_scan_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_surveydone_event_callback() 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() in rtw_scan_timeout_handler() to spin_lock_irq(). Otherwise, spin_lock_bh() will also cause deadlock() in timer handler. Signed-off-by: Duoming Zhou Link: https://lore.kernel.org/r/20220409061836.60529-1-duoming@zju.edu.cn Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/staging/rtl8723bs/core/rtw_mlme.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme.c b/drivers/staging/rtl8723bs/core/rtw_mlme.c index cf79bec916c5..2c20bf26b10e 100644 --- a/drivers/staging/rtl8723bs/core/rtw_mlme.c +++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c @@ -749,7 +749,9 @@ void rtw_surveydone_event_callback(struct adapter *adapter, u8 *pbuf) } if (check_fwstate(pmlmepriv, _FW_UNDER_SURVEY)) { + spin_unlock_bh(&pmlmepriv->lock); del_timer_sync(&pmlmepriv->scan_to_timer); + spin_lock_bh(&pmlmepriv->lock); _clr_fwstate_(pmlmepriv, _FW_UNDER_SURVEY); } @@ -1584,11 +1586,11 @@ void rtw_scan_timeout_handler(struct timer_list *t) mlmepriv.scan_to_timer); struct mlme_priv *pmlmepriv = &adapter->mlmepriv; - spin_lock_bh(&pmlmepriv->lock); + spin_lock_irq(&pmlmepriv->lock); _clr_fwstate_(pmlmepriv, _FW_UNDER_SURVEY); - spin_unlock_bh(&pmlmepriv->lock); + spin_unlock_irq(&pmlmepriv->lock); rtw_indicate_scan_done(adapter, true); } -- 2.35.1