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 C6B92C4167B for ; Thu, 7 Dec 2023 12:29:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379242AbjLGM24 (ORCPT ); Thu, 7 Dec 2023 07:28:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232186AbjLGM2z (ORCPT ); Thu, 7 Dec 2023 07:28:55 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8446084; Thu, 7 Dec 2023 04:29:01 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id d2e1a72fcca58-6ceba6c4b8dso199554b3a.1; Thu, 07 Dec 2023 04:29:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1701952141; x=1702556941; darn=vger.kernel.org; h=message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Lid62c13OA13UOuK4ZHFWJw8LQvMIM6OUlJkAmjS2aw=; b=R3pTQ2P71oWwOEsR3F+FIkrEDfQ3pb2aQ792ZWI3Bis/nQHdoXAHTnYxBDSAqoTupG YJEpF2z0uPtVSQAK7dqwfaMgfCqkJ39aUXN59pv19zGa9YTjmkjRYlJNGzbjxnKHaJ+7 NzsjEj/BYnw9GZzIzu8n3rIaQCZ8WEw646oZNGC+3+iN8iVgGm1KG21yjJNwBji4Hy1y VPkhsqd3AI+i0H4GxIxqd4UvbA/zVwQDExM9JtkCWDoAE0/1i+X+QIUsK7xdAup5qnih sGIzPaF4ZPHHDypCncitpbEmAjDGigG6M4Vabge6p3wFPyHPmc0Wps7RjoxNoayMvuak yZKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701952141; x=1702556941; h=message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Lid62c13OA13UOuK4ZHFWJw8LQvMIM6OUlJkAmjS2aw=; b=WijmHhYdGuDRUjuZHs8lAmj1b9T1YI+VIXqPYnMemH7KzvszBA7vVG9EKr7O4XHOdc vwui3hrDEchhn695g077pI/xbkz44/R6CK7XK3Yh9i9YxGMLZSWU/eaOCg1WL1ceeTjg V0PBT1dbtkXDPbw1R46Jd2p9HuguBwb7F+JeGnhjYE7WBJAku78FUq5g/OsM4U8PRYZM 7qF2QFLbcFzjwz1t7OUnJwSJis+302WWdJgShDzd2Xji2t/24TpSqSP73NcC0a6+Rc5C VVj5DtrWcmBEFz3VbOAp82eg5DddJEWTlXxbV2osmyovDv/xTT9hcvK8BnDZWl8/wFE3 b7cw== X-Gm-Message-State: AOJu0YwJ/GynaHtpkAUjZVmfinmPCM24NnYjbXPERMQOcxxxC5s4vZGg nEhklZD108jTzuqlqSJrldo= X-Google-Smtp-Source: AGHT+IGr5lKAfJ7n2y2wAOLF3nW2W2xMuYwvmOjmc39ExVmCK+JKLpfStp3stmFBqfVmX7pG1JBUcQ== X-Received: by 2002:a05:6a20:9381:b0:18d:b43:78ea with SMTP id x1-20020a056a20938100b0018d0b4378eamr2911595pzh.43.1701952140676; Thu, 07 Dec 2023 04:29:00 -0800 (PST) Received: from 377044c6c369.cse.ust.hk (191host097.mobilenet.cse.ust.hk. [143.89.191.97]) by smtp.gmail.com with ESMTPSA id x20-20020a056a00189400b006ce5066282bsm1164715pfh.34.2023.12.07.04.28.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 Dec 2023 04:29:00 -0800 (PST) From: Chengfeng Ye To: 3chas3@gmail.com, davem@davemloft.net, horms@kernel.org, kuba@kernel.org Cc: linux-atm-general@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Chengfeng Ye Subject: [PATCH v3 1/2] atm: solos-pci: Fix potential deadlock on &cli_queue_lock Date: Thu, 7 Dec 2023 12:28:49 +0000 Message-Id: <20231207122849.41798-1-dg573847474@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As &card->cli_queue_lock is acquired under softirq context along the following call chain from solos_bh(), other acquisition of the same lock inside process context should disable at least bh to avoid double lock. console_show() --> spin_lock(&card->cli_queue_lock) --> solos_bh() --> spin_lock(&card->cli_queue_lock) This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. To prevent the potential deadlock, the patch uses spin_lock_bh() on the card->cli_queue_lock under process context code consistently to prevent the possible deadlock scenario. Signed-off-by: Chengfeng Ye --- drivers/atm/solos-pci.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c index 94fbc3abe60e..95f768b28a5e 100644 --- a/drivers/atm/solos-pci.c +++ b/drivers/atm/solos-pci.c @@ -449,9 +449,9 @@ static ssize_t console_show(struct device *dev, struct device_attribute *attr, struct sk_buff *skb; unsigned int len; - spin_lock(&card->cli_queue_lock); + spin_lock_bh(&card->cli_queue_lock); skb = skb_dequeue(&card->cli_queue[SOLOS_CHAN(atmdev)]); - spin_unlock(&card->cli_queue_lock); + spin_unlock_bh(&card->cli_queue_lock); if(skb == NULL) return sprintf(buf, "No data.\n"); -- 2.17.1