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 94164C43334 for ; Mon, 13 Jun 2022 14:00:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380485AbiFMOAd (ORCPT ); Mon, 13 Jun 2022 10:00:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380322AbiFMNyG (ORCPT ); Mon, 13 Jun 2022 09:54:06 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9FA8A42A38; Mon, 13 Jun 2022 04:34:47 -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 4B701B80EC6; Mon, 13 Jun 2022 11:34:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BB973C34114; Mon, 13 Jun 2022 11:34:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655120085; bh=jCgpnnoSkDT54evi1luL+K6mgNflbygqRCA4lF4dyvI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tOUyzZTSV0L6KsnofJFkxe4zBS7B/oHcMeV9LbKgr4PKLOfcnXqILUUhFxdnr2D7/ xmmvYuhNHJSg6kA/szPQGh0A5yy25z97Fha1+HSbo5TdAe4JINgmA3QgBZSvXF+TvX 17I2SRa27TdEYcZDVBMwDr+21he2e3TdjKy9rQYo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Duoming Zhou , Sasha Levin Subject: [PATCH 5.18 229/339] drivers: staging: rtl8192eu: Fix deadlock in rtw_joinbss_event_prehandle Date: Mon, 13 Jun 2022 12:10:54 +0200 Message-Id: <20220613094933.605536236@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094926.497929857@linuxfoundation.org> References: <20220613094926.497929857@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 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