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 7DEB07F for ; Tue, 7 Jun 2022 17:56:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F7C4C3411C; Tue, 7 Jun 2022 17:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624583; bh=BqpPVKGOyzA+uqnI406r2teKN9d313jC11ZUQ6CBH3Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=keOX2bxHfI7M1CE9oJe1C2VL6HveflnoRMIcXPXBD2DInzr52lg8/1IhxvzluP6p7 LcekVkbPJfviPfxvMlgSlG8q/tze6QltckONe2O0fa9tVPxl/zjYnAsYVoW77t1ko0 uFIuLq6TwNE9Duvj2Hujb2/MbcwZiceFTwZdFVMgz5iii5z/KMylHPv/blF8rI8D0s jzr4VqP/Nv+ZuP7Rt4wrjCgNVhMvhqEEdtOTaltr3FTgwgsIEOVQxIlGy/DtggDaGg ZNSleZNvbM7YRvFVU/3zRXl2LwAMayR8PlHlLSmqENGbXwbhyCVq7twykphHkTWdi/ GTHE3qrlRp1aA== 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 06/51] drivers: staging: rtl8192bs: Fix deadlock in rtw_joinbss_event_prehandle() Date: Tue, 7 Jun 2022 13:55:05 -0400 Message-Id: <20220607175552.479948-6-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> 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 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 2c20bf26b10e..952c3e14d1b3 100644 --- a/drivers/staging/rtl8723bs/core/rtw_mlme.c +++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c @@ -1238,8 +1238,10 @@ 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)); } @@ -1545,7 +1547,7 @@ 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) { @@ -1573,7 +1575,7 @@ void _rtw_join_timeout_handler(struct timer_list *t) } - spin_unlock_bh(&pmlmepriv->lock); + spin_unlock_irq(&pmlmepriv->lock); } /* -- 2.35.1