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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26856C56202 for ; Wed, 18 Nov 2020 08:02:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B26EC20B80 for ; Wed, 18 Nov 2020 08:02:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OZEH5p2/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726685AbgKRICs (ORCPT ); Wed, 18 Nov 2020 03:02:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35882 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725794AbgKRICs (ORCPT ); Wed, 18 Nov 2020 03:02:48 -0500 Received: from mail-pg1-x542.google.com (mail-pg1-x542.google.com [IPv6:2607:f8b0:4864:20::542]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26621C0613D4 for ; Wed, 18 Nov 2020 00:02:48 -0800 (PST) Received: by mail-pg1-x542.google.com with SMTP id i13so635327pgm.9 for ; Wed, 18 Nov 2020 00:02:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=1MznaoaWYPhILjK6Iw2zxEvLXxblXieEgx/j6qplbWo=; b=OZEH5p2/Ey6xsEgcxVjk2KnO7FcOPg7SgJQiypZusHEOEdM2i2T/NzHudHqZrk/iD6 cWYDciD29PDUBxrX001+qFsD2d5q0hZUEUUeXCSdbO3y493BY8NwvQat6DpEXXqvFG3q /Q4JIh+Pkzt/HApb8uSkY7ye3WGi3DxxuOhQJbaUDb0GE9uW0PnoaOYAEEmTJC4HuvoK g9fndS1D8Suk7JhiH53v6OoW9pfgqHIG9rbEnzwSwshIVBZJ/G1UGAarBdoU6KDleSoK ioqxVT8sk1ht+aMUPk2CmfEMJ2qgxmMHPNEfb/RNzEpO1XAIZZpH/wDSdyJbhS/NkPvp fEsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=1MznaoaWYPhILjK6Iw2zxEvLXxblXieEgx/j6qplbWo=; b=DfHAhNytYezrUdBjpvNix1O535mO48nMGKMuxKK0mEeSYU+6BY2WpD1dp522bBbCvB wHcd/nK+mJkkKP0om64zYu2PrtAlc8I/OrppmHGATbtIOprC+MulMCPhyXX5yN27Y6bX mMX6Wg1oy/7wm1ZbIfrnlZKsaA8CmnpMjaWc5uGMdYK8FQfHbdfsxMGhG5aijNhcalyR fafEpb/saghzc7ipoHHJ9ghltx59MzsdyErz+wImo5wuo1uZ+e/20+Jl3LcpXyTct9C8 zauI72G9qRa6lPzHU0Yyctknrr06+VP0pkz9hPxagVtBNQS4SDdP8BaWMs5kR0rOfAAv DePQ== X-Gm-Message-State: AOAM533xdnE7ivSYb/+zl8YX058gaoz6lINMYY7faAHm9nim5RjL+eux uRxY1E+UzwsrQFwdWSU6Q9I= X-Google-Smtp-Source: ABdhPJwxwr5pDZsF+oXOFKlhhkSq+JDhp7dwTvj+0ac39w/2ikbtuX2Ic6nJMYhy6zZV5GNnHeUX5Q== X-Received: by 2002:a63:1901:: with SMTP id z1mr6775411pgl.87.1605686567722; Wed, 18 Nov 2020 00:02:47 -0800 (PST) Received: from adolin ([49.207.220.203]) by smtp.gmail.com with ESMTPSA id q19sm24924365pfh.37.2020.11.18.00.02.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Nov 2020 00:02:47 -0800 (PST) Date: Wed, 18 Nov 2020 13:32:42 +0530 From: Sumera Priyadarsini To: Julia.Lawall@lip6.fr Cc: Gilles.Muller@lip6.fr, nicolas.palix@imag.fr, michal.lkml@markovi.net, cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org Subject: [PATCH v2] coccinelle: locks: Add balancedlock.cocci script Message-ID: <20201118080242.t6u6lchj5ww2fac4@adolin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When acquiring locks under certain conditions, they must be released under the same conditions as well. However, sometimes, there may be missing unlocks which may lead to a potential deadlock. Add this script to detect such code segments and avoid potential deadlock situations. Signed-off-by: Sumera Priyadarsini --- Changes in v2(as suggested by Markus): - Modify usage of position variable - Modify comments - Add dependencies for rules --- scripts/coccinelle/locks/balancedlock.cocci | 164 ++++++++++++++++++++ 1 file changed, 164 insertions(+) create mode 100644 scripts/coccinelle/locks/balancedlock.cocci diff --git a/scripts/coccinelle/locks/balancedlock.cocci b/scripts/coccinelle/locks/balancedlock.cocci new file mode 100644 index 000000000000..9684a9920f79 --- /dev/null +++ b/scripts/coccinelle/locks/balancedlock.cocci @@ -0,0 +1,164 @@ +/// Sometimes, locks that are acquired under certain conditions may have +/// missing unlocks leading to a potential deadlock situation. This +/// semantic patch detects such cases. +//# False positives may be generated due to locks released within a nested +//# function call or a goto block. +/// +// Confidence: Moderate +// Copyright: (C) 2020 Julia Lawall INRIA/LIP6 +// Copyright: (C) 2020 Sumera Priyadarsini + +virtual context +virtual org +virtual report + + +@prelocked@ +expression E; +position p; +@@ + +( +mutex_lock@p(E); +| +read_lock@p(E); +| +write_lock@p(E); +| +spin_lock@p(E); +| +spin_lock_bh@p(E); +| +spin_lock_irqsave@p(E, ...); +| +read_lock_irqsave@p(E, ...); +| +write_lock_irqsave@p(E, ...); +| +raw_spin_lock@p(E); +| +raw_spin_lock_irq@p(E); +| +raw_spin_lock_bh@p(E); +| +local_lock@p(E); +| +local_lock_irq@p(E); +| +local_lock_irqsave@p(E, ...); +| +read_lock_irq@p(E); +| +read_lock_bh@p(E); +| +write_lock_bh@p(E); +) + +@balanced@ depends on context || org || report@ +position prelocked.p; +position pif; +expression e,prelocked.E; +statement S1,S2; +identifier lock; +identifier unlock={mutex_unlock, + spin_unlock, + spin_unlock_bh, + spin_unlock_irqrestore, + read_unlock_irqrestore, + write_unlock_irqrestore, + raw_spin_unlock, + raw_spin_unlock_irq, + raw_spin_unlock_bh, + local_unlock, + local_unlock_irq, + local_unlock_irqrestore, + read_unlock_irq, + read_unlock_bh, + write_unlock_bh + }; +@@ + +if (e) { + ... when any +lock@p(E, ...) + ... when != E + when any +} else S1 +... when != E + when any +if@pif (e) { + ... when != E + when any + unlock(E, ...); + ... when any +} else S2 +... when != E + when any + +// ---------------------------------------------------------------------------- + +@balanced2 depends on context || org || report@ +identifier lock, unlock = {mutex_unlock, + spin_unlock, + spin_unlock_bh, + spin_unlock_irqrestore, + read_unlock_irqrestore, + write_unlock_irqrestore, + raw_spin_unlock, + raw_spin_unlock_irq, + raw_spin_unlock_bh, + local_unlock, + local_unlock_irq, + local_unlock_irqrestore, + read_unlock_irq, + read_unlock_bh, + write_unlock_bh + }; +expression E, f, x; +statement S1, S2, S3, S4; +position prelocked.p, balanced.pif; +position j0, j1, j2, j3; +@@ + +* lock@j0@p(E, ...); +... when != E; + when != if@pif (...) S1 else S2 + when any +x@j1 = f(...); +* if (<+...x...+>) +{ + ... when != E; + when forall + when != if@pif (...) S3 else S4 +* return@j2 ...; +} +... when any +* unlock@j3(E, ...); + +// ---------------------------------------------------------------------------- + +@script:python balanced2_org depends on org@ +j0 << balanced2.j0; +j1 << balanced2.j1; +j2 << balanced2.j2; +j3 << balanced2.j3; +@@ + +msg = "This code segment might have an unbalanced lock." +coccilib.org.print_todo(j0[0], msg) +coccilib.org.print_link(j1[0], "") +coccilib.org.print_link(j2[0], "") +coccilib.org.print_link(j3[0], "") + +// ---------------------------------------------------------------------------- + +@script:python balanced2_report depends on report@ +j0 << balanced2.j0; +j1 << balanced2.j1; +j2 << balanced2.j2; +j3 << balanced2.j3; +@@ + +msg = "This code segment might have an unbalanced lock around lines %s,%s,%s." % (j1[0].line,j2[0].line,j3[0].line) +coccilib.report.print_report(j0[0], msg) + -- 2.25.1