From patchwork Tue Sep 13 23:31:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luiz Augusto von Dentz X-Patchwork-Id: 12975429 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 4FC06ECAAD8 for ; Tue, 13 Sep 2022 23:32:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229456AbiIMXcD (ORCPT ); Tue, 13 Sep 2022 19:32:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbiIMXcC (ORCPT ); Tue, 13 Sep 2022 19:32:02 -0400 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 35D0171BD7 for ; Tue, 13 Sep 2022 16:32:00 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id c2so13390914plo.3 for ; Tue, 13 Sep 2022 16:32:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date; bh=Sth9s6jFuAgyrkcRmgl3qDDWKNFIt5yzW79ugW82O8E=; b=b1TAbHUvUSmMva7ETzGd/2dJOh1gjLOnBBiy53mS4RC5YIDyvk5XynEEZimYjcDQeb 5rlAQBe6s0hptP3ECuD0mJKyql7DzKq4MDut8LI20Nz2CFQXp+dH+31sOzdxOsxmtZEM O7isnHd9ZIdfPmIg3UvZgINU9PE4w9SLYu/emKrO23fNdSiSiWSSMt8OtzL6LXR/Vkd0 pWM3u4/kLdEoA/ljeFycPmD6+083QkUDHWOcamqQAAfVJeOQtgmrP2QvBSzlaF0PwvuP Sis7LvXBCpj2pa5CmKC1JXktp4bp81aKbTfpWDirz3PXQ9wIrIA/Hk25uq/CBwAWBnTB smJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-message-state:from:to:cc:subject:date; bh=Sth9s6jFuAgyrkcRmgl3qDDWKNFIt5yzW79ugW82O8E=; b=ohFSbnAl5rkGSzSkOdLZgedQl+7cbILLZL3kzwBHvd6m14Pf2cvdUFTuoN9BghitVn wSUUgLs3Xg4uMKThPxZnT3w97WJSGqa0A5xvtM450q44JT44irgjFpBPcVUjPTltdqf4 s9dLffU/Rcgfode4EfCkkWQhCtwdkKcXKNn82Vsxnhg949hNkwwIqAQQEkjW7qQ/f+Fa YyAqdsZUxdYEF0dquIOf63wg15bDKxApfDjHcVFuDmc1sUBEuzN+nWzfqjO+lCMlKBFe 4KxNHEeB5ix3QgiKXicukaZzoP9P149JiJEVeEaas73i7H2qU3SSXMFt6fPP8cdvaG2U l2kA== X-Gm-Message-State: ACrzQf0yArHDz1yqLFWFGJZYBWwuBvY2Iekd1f8SPh20b+7c9jcERFwz 6CMw0lyTd+PbhqK5X4tfCpbbR2RyHVzS/acs X-Google-Smtp-Source: AMsMyM4QxuRv+9qfrAnU34/SN0HLN2WfSM/+CahAeeIh4j/iUmeopxmtOyxH9fhBwt6oLXvgclYc5w== X-Received: by 2002:a17:90a:8b92:b0:202:c361:9dba with SMTP id z18-20020a17090a8b9200b00202c3619dbamr1655341pjn.62.1663111918942; Tue, 13 Sep 2022 16:31:58 -0700 (PDT) Received: from lvondent-mobl4.. (c-71-56-157-77.hsd1.or.comcast.net. [71.56.157.77]) by smtp.gmail.com with ESMTPSA id n18-20020a170903111200b00174d4fabe76sm9010599plh.214.2022.09.13.16.31.57 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Sep 2022 16:31:58 -0700 (PDT) From: Luiz Augusto von Dentz To: linux-bluetooth@vger.kernel.org Subject: [PATCH] Bluetooth: RFCOMM: Fix possible deadlock on socket shutdown/release Date: Tue, 13 Sep 2022 16:31:57 -0700 Message-Id: <20220913233157.526041-1-luiz.dentz@gmail.com> X-Mailer: git-send-email 2.37.3 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org From: Luiz Augusto von Dentz Due to change to switch to use lock_sock inside rfcomm_sk_state_change the socket shutdown/release procedure can cause a deadlock: rfcomm_sock_shutdown(): lock_sock(); __rfcomm_sock_close(): rfcomm_dlc_close(): __rfcomm_dlc_close(): rfcomm_dlc_lock(); rfcomm_sk_state_change(): lock_sock(); To fix this when the call __rfcomm_sock_close is now done without holding the lock_sock since rfcomm_dlc_lock exists to protect the dlc data there is no need to use lock_sock in that code path. Link: https://lore.kernel.org/all/CAD+dNTsbuU4w+Y_P7o+VEN7BYCAbZuwZx2+tH+OTzCdcZF82YA@mail.gmail.com/ Fixes: b7ce436a5d79 ("Bluetooth: switch to lock_sock in RFCOMM") Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/rfcomm/sock.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index 4bf4ea6cbb5e..21e24da4847f 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -902,7 +902,10 @@ static int rfcomm_sock_shutdown(struct socket *sock, int how) lock_sock(sk); if (!sk->sk_shutdown) { sk->sk_shutdown = SHUTDOWN_MASK; + + release_sock(sk); __rfcomm_sock_close(sk); + lock_sock(sk); if (sock_flag(sk, SOCK_LINGER) && sk->sk_lingertime && !(current->flags & PF_EXITING))