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=-13.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 9AF8FC433E1 for ; Fri, 7 Aug 2020 20:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7CF90214F1 for ; Fri, 7 Aug 2020 20:10:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rwP2TF51" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726948AbgHGUKh (ORCPT ); Fri, 7 Aug 2020 16:10:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726898AbgHGUKd (ORCPT ); Fri, 7 Aug 2020 16:10:33 -0400 Received: from mail-ot1-x342.google.com (mail-ot1-x342.google.com [IPv6:2607:f8b0:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2D8DC061756 for ; Fri, 7 Aug 2020 13:10:33 -0700 (PDT) Received: by mail-ot1-x342.google.com with SMTP id a65so2533904otc.8 for ; Fri, 07 Aug 2020 13:10:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=0CPJ8TX97O10k1WA8Nz1yzDJbecwdHeNRDb3T87/dhc=; b=rwP2TF51TdVM6KM7FvBbzn6N+2xMsWCSAsVEeY/3g0sF8fh+N2XuPS9wws4islxelQ 4hew9G5ONEcACADFvPNiFzLtT0EeFSN/9lq/egiEKfPN3y7CDW//zoTuj0y3KUTltXUC e/a6HbEK2gJrblulTNvIpelalM5JVar6q4Rm4RpEZWFHRkMi0L+ds8r601ufH+w4Rr8h W9PMxXMknVZHnDLFlPPdZ5ncTce5q/ueENprxqzDwvkC4VE0zTO+JKiEsrimeXJFo51F 3I3yVuJ1lxLEYmW2XbxxVY0tLiwtPKVnzBHp8GAtfuvPJ2cls3S/Fd/b0U0qt2CGUhJ7 7xpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=0CPJ8TX97O10k1WA8Nz1yzDJbecwdHeNRDb3T87/dhc=; b=KO1JNNUB7+ZJ8rhIc/BxwJlmIHjtKM4l1fT04Nyli0x/4+V3yOitW8361IdKKYhk2+ h60L61a6MBBThwzyOz9xYu3Yu3CdB4N0xHXfhW7EEO5SBDBCZ1dFVGn+uZFVpIidNNhh hh1T7g+ynOnPHhgASqwPUfn0QNSP7CFsI1jFdE/OSPNAk2Q4Xa0ZRw9ZpCObsCKgFtyf tCJ8JP6EcLyxZoV2Q+Zq/b50NxaprgNf4TzIl2bKsKfwvsrzXJZZCIBpxsEMGSazJdgk UwENqscmDUIZfiiIn1zIaCUN+6poVey7wPogMvDNn/q6DFB52oOkhOEXixfYuGOIWyqj D1fQ== X-Gm-Message-State: AOAM53078g4ePy21lgyPODKvIW1Gf2BfUVts9RyYCU7Xk9tZJ/xf1e5l X01/kLnUQJc1erHHCoSjjYg= X-Google-Smtp-Source: ABdhPJyu60B90i33U1ZZDCkiDwHpAsMMj4v2uPYHrKxOB/qbmXa4CoU0GkEgEgDSpSN/IsVohmGu6A== X-Received: by 2002:a9d:6e6:: with SMTP id 93mr13473271otx.370.1596831033097; Fri, 07 Aug 2020 13:10:33 -0700 (PDT) Received: from frodo.hsd1.co.comcast.net ([2601:284:8204:6ba0::af38]) by smtp.googlemail.com with ESMTPSA id s6sm1835794otq.75.2020.08.07.13.10.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Aug 2020 13:10:32 -0700 (PDT) From: Jim Cromie To: jbaron@akamai.com, linux-kernel@vger.kernel.org Cc: Jim Cromie Subject: [PATCH 8/8] dyndbg: add locking around zpool-add loop in zpool-init Date: Fri, 7 Aug 2020 14:09:56 -0600 Message-Id: <20200807200957.1269454-10-jim.cromie@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200807200957.1269454-1-jim.cromie@gmail.com> References: <20200807200957.1269454-1-jim.cromie@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org summary: no fix here. Locking review: ddebug_zpool_init(), like other *_init() routines, does not run under a lock (that we control). Unlike them, it runs later, at late_init. I dont know whether this is pertinent to the kernel panic. ddebug_callsite_get/put() are called as a pair under mutex-lock for all 3 callsite users; dynamic_emit_prefix() does its own ABBA-ish LGPU (Lock-Get-Put-Unlock), as does ddebug_change(). ddebug_proc_show() does GP, ddebug_proc_start|stop() wrap it with LU. ddebug_add_module() does LU to protect list_add(), HEAD~x added ddebug_zpool_add() inside that protection. This commit adds locking to ddebug_zpool_init(), around the loop of ddebug_zpool_add(), to match the locking in ddebug_add_module(). Signed-off-by: Jim Cromie --- lib/dynamic_debug.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 9c51f24a9c66..716231a98910 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -1187,8 +1187,10 @@ static void __init ddebug_zpool_init(void) } /* add-module normally does this, but not in time for builtins */ + mutex_lock(&ddebug_lock); for (iter = __start___dyndbg; iter < __stop___dyndbg; iter++) ddebug_zpool_add(iter); + mutex_unlock(&ddebug_lock); v2pr_info("total pages: %lu compaction: %lu\n", zs_get_total_pages(dd_callsite_zpool), @@ -1285,4 +1287,3 @@ early_initcall(dynamic_debug_init); /* Debugfs setup must be done later */ fs_initcall(dynamic_debug_init_control); - -- 2.26.2