From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 936F67F for ; Tue, 7 Jun 2022 17:53:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75B11C3411C; Tue, 7 Jun 2022 17:53:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624399; bh=uTEg04H4UeGHZAZVp/bvD+TiVLWrnnrWSihosKeUwgw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lX44tFINdJ2lymCOoYvcn+SSB+E3eUzw8spPZFs6CRid5+KuTHS1zXUf0Pf0qQt7h 5HQ/eeq7nsyVPJS9xgZOLY2jRiIvDx1RI9+hPOSyWSImVvxOMmz7iMm6z5xDnBJBlH URiyV6emQ1FFRdpXFdVbQFKlnD8gw9++53NLDWdHV/fpOR7yVfXGoM7HJaxNE/2Muv tC9VxETdimk/CH6GottScPP/xHcmQaPBpOdC/HtOGp800O2j5SCv8h1KWCg2Pf28Jx 9d40bYW7iOE0jYO9xdgZydbV5ulBM5DmHoTmgH9z4NCMTkIB3r6B3uBeOIs7Qpw91H isWZm3OJnZUmQ== 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 5.17 05/60] drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback() Date: Tue, 7 Jun 2022 13:52:02 -0400 Message-Id: <20220607175259.478835-5-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607175259.478835-1-sashal@kernel.org> References: <20220607175259.478835-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit 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 9202223ebc0c..a6e5f2332e12 100644 --- a/drivers/staging/rtl8723bs/core/rtw_mlme.c +++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c @@ -751,7 +751,9 @@ 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); } @@ -1586,11 +1588,11 @@ 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