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 80F14C43217 for ; Mon, 7 Feb 2022 15:44:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383775AbiBGPnN (ORCPT ); Mon, 7 Feb 2022 10:43:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384370AbiBGPb4 (ORCPT ); Mon, 7 Feb 2022 10:31:56 -0500 Received: from mail-pf1-x430.google.com (mail-pf1-x430.google.com [IPv6:2607:f8b0:4864:20::430]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C7A7C03E961; Mon, 7 Feb 2022 07:31:37 -0800 (PST) Received: by mail-pf1-x430.google.com with SMTP id v74so13569132pfc.1; Mon, 07 Feb 2022 07:31:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:content-language:to:cc:from :subject:content-transfer-encoding; bh=9brYQ3v7OVc6aEBTBtZMjzX9d5bnamj1rQekxmQrM9M=; b=I2Hf3GJxvNN4GRQH9kzLzxkqg8wf5jNqWqCXxsh1evsCBxY1LousIr1ABLvbNRpZC5 HlYY5mDuvP2NKqMMC7qNafgtUw+Km/TojstZobIlg68g+0cQkjgZh17Y/nuEywZEYo7H x9+9GyWtPmINGOI7gSyEi+sEXPT6CPp3bA712Md2doEvBjSIszMyc/KbxqZIbBr1zmCV XX5Bdj1guw9UwtLRcdzGIMJiriiT0XVSl0OvDwrT8J2kXe3zR6e0dFETRcBxA9sVxRI4 4pPQQKc4jXKe9ztRQlrGh52wXDeBaa7Usc67hbV/UZ2Kw/MIpXW/B0iO7gngV3Ayf3+9 RoCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent :content-language:to:cc:from:subject:content-transfer-encoding; bh=9brYQ3v7OVc6aEBTBtZMjzX9d5bnamj1rQekxmQrM9M=; b=LahahQibRmZXcl0RimloLQ+Ak5YIEt34xGK2UB55ynszmTsNwGcXLF9UqzaaNNCgfY UdXaNW7TDNQlRqcwlleh1c/kC3Upo8/cI3C7di/cKfLiJtfp6clI+jLZ/g0/vOokl1BE D/zinOKyQZ580gmJJRMFPqcx4Wg2gek5YhSgdwN1stoDTx+Eiy6WOrVll1/1UQTLNvqO 7XDGvkXGp4NH5P12pdbw7hM5/VektZ0KJuaO3flldEWb0GxCryL47lK3nygf8C80ia+O HhY5mwCie+13VNOUod4mjwuUGY2t2v3z75m+mmSV8LjcAaplzdtxbq18KedOZdoJ+5hx uO+Q== X-Gm-Message-State: AOAM530eJj7NrfbJM0rp1mpDMNLzMXYDf/IzXEDsQ1nMd5cGlMjOe133 rqsFloB4Dz+2NZVcwdxRUWQ= X-Google-Smtp-Source: ABdhPJwGYDQw/0+EXbLlKn7bGPKQ8vZxLWGxgt4AIK9ImLm+DbN1g0CjOUZmNo8FI5+oxy/Ulb2i8Q== X-Received: by 2002:a05:6a00:218b:: with SMTP id h11mr16337091pfi.29.1644247896825; Mon, 07 Feb 2022 07:31:36 -0800 (PST) Received: from [10.59.0.6] ([85.203.23.80]) by smtp.gmail.com with ESMTPSA id mn7sm2350149pjb.8.2022.02.07.07.31.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Feb 2022 07:31:36 -0800 (PST) Message-ID: Date: Mon, 7 Feb 2022 23:31:26 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Content-Language: en-US To: chunkeey@googlemail.com, kvalo@kernel.org, davem@davemloft.net, kuba@kernel.org Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org From: Jia-Ju Bai Subject: [BUG] intersil: p54: possible deadlock in p54_remove_interface() and p54_stop() Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, My static analysis tool reports a possible deadlock in the p54 driver in Linux 5.16: p54_remove_interface()   mutex_lock(&priv->conf_mutex); --> Line 262 (Lock A) wait_for_completion_interruptible_timeout(&priv->beacon_comp, HZ); --> Line 271 (Wait X) p54_stop()   mutex_lock(&priv->conf_mutex); --> Line 208 (Lock A)   p54p_stop() (call via priv->stop)     p54_free_skb()       p54_tx_qos_accounting_free()         complete(&priv->beacon_comp); --> Line 230 (Wake X) When p54_remove_interface() is executed, "Wait X" is performed by holding "Lock A". If p54_stop() is executed at this time, "Wake X" cannot be performed to wake up "Wait X" in p54_remove_interface(), because "Lock A" has been already hold by p54_remove_interface(), causing a possible deadlock. I find that "Wait X" is performed with a timeout, to relieve the possible deadlock; but I think this timeout can cause inefficient execution. I am not quite sure whether this possible problem is real and how to fix it if it is real. Any feedback would be appreciated, thanks :) Best wishes, Jia-Ju Bai