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 260C3C43334 for ; Tue, 7 Jun 2022 18:33:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352072AbiFGSdS (ORCPT ); Tue, 7 Jun 2022 14:33:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42082 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352493AbiFGSbC (ORCPT ); Tue, 7 Jun 2022 14:31:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 290ED17B879; Tue, 7 Jun 2022 10:56:20 -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 80454B82370; Tue, 7 Jun 2022 17:56:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 300E8C3411C; Tue, 7 Jun 2022 17:56:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624578; bh=UZ5Dc/FfKOsM7z4voa90CsZSNexUen7lsXLITcFOEA0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UN62sF+mpPPJ42eqCkhdV3XEPvr39T08XBLBUgiKCtFQlfN02PUyb9Zqzn3XhfpLS MQAljBPlMhi/T0ptZOcxZ2hDnJTQRGwfw4tv0LYgP8xsyw7JHbmCQRYVJFfIpJpDq5 cxp8M8u+KUY+8DuTLlsKlwcvnjt2/4P+5wkBkuqwvgrsUkvzfQzvxgBKmPo8EsxN5e n8QkAM53gJKwpirA4rt15ow7hNZ5oA+MuLYQfVbTmsocT6LS9g1Y0EtRs1GJvk5a0/ y5mTPTfI4+bDPeO9PWxMjq+oND6agEGOWrYZqdszVr8Th18mks7qklO9IUyZ3Hzlsy 6+iYkFOp5ovZA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Duoming Zhou , Greg Kroah-Hartman , Sasha Levin , fabioaiuto83@gmail.com, hdegoede@redhat.com, sevinj.aghayeva@gmail.com, linux-staging@lists.linux.dev Subject: [PATCH AUTOSEL 5.15 05/51] drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback() Date: Tue, 7 Jun 2022 13:55:04 -0400 Message-Id: <20220607175552.479948-5-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607175552.479948-1-sashal@kernel.org> References: <20220607175552.479948-1-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 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