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 709A3CCA48E for ; Mon, 13 Jun 2022 14:34:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1384768AbiFMOeh (ORCPT ); Mon, 13 Jun 2022 10:34:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1385401AbiFMObJ (ORCPT ); Mon, 13 Jun 2022 10:31:09 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D055AAB0F6; Mon, 13 Jun 2022 04:48:53 -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 AE736B80ECD; Mon, 13 Jun 2022 11:48:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FB5AC34114; Mon, 13 Jun 2022 11:48:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655120905; bh=BBbKxzBTSgGkElDL5HOf2Rr4T8+XctVQOFZU15enauU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cYCtM5MhIakcHE0j2FQkMRko13ATHHUrwJZcddUxvTDjIgClxp8n6rb30yECiCclH //j1VrI6xsQrCvXToZT1gwFa5NQFOY0ZjHq2SKEWvH9M/S/6l2NS+iSrda4tCrtaGV 6F9fMlm85Xbsi5cZZChSO/ecQ+89bqLNr9Sh3yiA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Duoming Zhou , Sasha Levin Subject: [PATCH 5.17 201/298] drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle() Date: Mon, 13 Jun 2022 12:11:35 +0200 Message-Id: <20220613094931.201356439@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094924.913340374@linuxfoundation.org> References: <20220613094924.913340374@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 041879b12ddb0c6c83ed9c0bdd10dc82a056f2fc ] 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() 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/20220409064953.67420-1-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 a6e5f2332e12..c29e3c68e61e 100644 --- a/drivers/staging/rtl8723bs/core/rtw_mlme.c +++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c @@ -1240,8 +1240,10 @@ void rtw_joinbss_event_prehandle(struct adapter *adapter, u8 *pbuf) spin_unlock_bh(&pmlmepriv->scanned_queue.lock); + 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)); } @@ -1547,7 +1549,7 @@ void _rtw_join_timeout_handler(struct timer_list *t) if (adapter->bDriverStopped || adapter->bSurpriseRemoved) return; - spin_lock_bh(&pmlmepriv->lock); + spin_lock_irq(&pmlmepriv->lock); if (rtw_to_roam(adapter) > 0) { /* join timeout caused by roaming */ while (1) { @@ -1575,7 +1577,7 @@ void _rtw_join_timeout_handler(struct timer_list *t) } - spin_unlock_bh(&pmlmepriv->lock); + spin_unlock_irq(&pmlmepriv->lock); } /* -- 2.35.1