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 B82E6C433FE for ; Tue, 26 Apr 2022 19:03:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353909AbiDZTGX (ORCPT ); Tue, 26 Apr 2022 15:06:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353806AbiDZTFu (ORCPT ); Tue, 26 Apr 2022 15:05:50 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A76A719A4AF; Tue, 26 Apr 2022 12:02:42 -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 sin.source.kernel.org (Postfix) with ESMTPS id 0A873CE20EA; Tue, 26 Apr 2022 19:02:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C23AC385B0; Tue, 26 Apr 2022 19:02:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650999759; bh=xCiJZCZ9ZeZ92LkRF+pni1gvqdOIeeTL+TY9tYDqNAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hsGdXgn1j08bU7TQSxiH2Ms1QZ+gIL3C6m4Puogyk3iaN+G9Ho8IadtsKIVV3iUzz Q4+WnDdAxbxQ1ivC+fD5ACwQugrDDMfHxcnl4iowo8XErQOCrypw1EElF9kZxS8oLC /kdskgmZB9WqVEDDl5M43Jj7WMCcu7S/xzxLR1UQbneiSqwbDYk+DffetNDl9xShLx rWbRubkpiuVJzM8onPeRjGddVA9ZJ031PU/G/FWhuNWkvvi/0HauL8WpZhLP2vksGL CV/Tck/hEibm1XkGkuAqlwNf804V8PEuKsUAy4qCWC0KPFV2wwZ/AjP9r88toeET4P WrDbf6FD27dew== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Duoming Zhou , Paolo Abeni , Sasha Levin , jes@trained-monkey.org, davem@davemloft.net, kuba@kernel.org, linux-hippi@sunsite.dk, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 7/9] drivers: net: hippi: Fix deadlock in rr_close() Date: Tue, 26 Apr 2022 15:02:28 -0400 Message-Id: <20220426190232.2351606-7-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220426190232.2351606-1-sashal@kernel.org> References: <20220426190232.2351606-1-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 bc6de2878429e85c1f1afaa566f7b5abb2243eef ] There is a deadlock in rr_close(), which is shown below: (Thread 1) | (Thread 2) | rr_open() rr_close() | add_timer() spin_lock_irqsave() //(1) | (wait a time) ... | rr_timer() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold rrpriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need rrpriv->lock in position (2) of thread 2. As a result, rr_close() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_irqsave(), which could let timer handler to obtain the needed lock. Signed-off-by: Duoming Zhou Link: https://lore.kernel.org/r/20220417125519.82618-1-duoming@zju.edu.cn Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/hippi/rrunner.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/hippi/rrunner.c b/drivers/net/hippi/rrunner.c index 22010384c4a3..b9646b369f8e 100644 --- a/drivers/net/hippi/rrunner.c +++ b/drivers/net/hippi/rrunner.c @@ -1353,7 +1353,9 @@ static int rr_close(struct net_device *dev) rrpriv->fw_running = 0; + spin_unlock_irqrestore(&rrpriv->lock, flags); del_timer_sync(&rrpriv->timer); + spin_lock_irqsave(&rrpriv->lock, flags); writel(0, ®s->TxPi); writel(0, ®s->IpRxPi); -- 2.35.1