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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C2ADC87FCB for ; Mon, 4 Aug 2025 18:28:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2B0EB6B00A7; Mon, 4 Aug 2025 14:28:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2883D6B00A8; Mon, 4 Aug 2025 14:28:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1CA196B00A9; Mon, 4 Aug 2025 14:28:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 0D29C6B00A7 for ; Mon, 4 Aug 2025 14:28:50 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 96A7681697 for ; 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dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1754332128; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dAN+Q6z4xYDkwzhyRANAgXGazj/lNfVPId+ttt9Jaos=; b=K92bmUc71j9vQSxCZ/u/PseQbVOwJh7a3bTq0g8ulR0h0m7y3g9nlcz4/shvCQlvxHpjBy INxi2zomsdiWXg19PdTuHZGVqHCzFnsHXqKWyfjPNptqGRepxsqnOhg/pZw7l7+m9l9mey K5fFNsnuW4o+46JkI0jKo5GMsRnO83Y= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id BA7515C629D; Mon, 4 Aug 2025 18:28:46 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8AE3C4CEE7; Mon, 4 Aug 2025 18:28:44 +0000 (UTC) Date: Mon, 4 Aug 2025 19:28:42 +0100 From: Catalin Marinas To: Breno Leitao Cc: Andrew Morton , Waiman Long , Gu Bowen , stable@vger.kernel.org, linux-mm@kvack.org, Lu Jialin Subject: Re: [PATCH] mm: Fix possible deadlock in console_trylock_spinning Message-ID: References: <20250730094914.566582-1-gubowen5@huawei.com> <20250801153303.cee42dcfc94c63fb5026bba0@linux-foundation.org> <5ca375cd-4a20-4807-b897-68b289626550@redhat.com> <20250801205323.70c2fabe5f64d2fb7c64fd94@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D165B40004 X-Stat-Signature: d5qsr6auaxnb7m4mqisf5x1n7k3rfizj X-HE-Tag: 1754332127-488484 X-HE-Meta: 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 WsWEsHuJ tqd3CiNiUpsStQhGAOFC3nCa80yRdhz44/iZ6teO1EYa/ywH5P335iYc14r6wMY0+M/Vc0eN++YAe4U1BbjXtSM/e/xoX0EM849PScEFQWHrMi0Y8pTB8xZPP03FzOwEwZHJmwPgVmRSZRRGpNsMdItBTR+rGa4Z9WwCjCcmKuMyCYtLxQyWWP/Sa4XkyxD+PbDthvQHkW2T77JVSkELev03IjoCJ3zdqzYnASfK3U3V794G8xWdgF2wpY1pioXmuxx7o5idTb3mOOJtl9RzqYKZiAWOZupzP6WG6EEck2M0FDQdQgkg4rGRoxtODxcyO1zfgsCrs61CnmZLl3xtFvpOnUT+jMjfa/VAJFg7wnUNzBfaPoYhl3DrW2dax9Vdwhs2cJd2pXs8iqfg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Aug 04, 2025 at 05:34:10AM -0700, Breno Leitao wrote: > On Mon, Aug 04, 2025 at 01:08:15PM +0100, Catalin Marinas wrote: > > > I'm surprised we haven't seen these until recently. Has printk always > > allocated memory? > > I can talk about netconsole, and the answer is yes! > > weird enought, lockdep never picked this issue, and I have a few set of > hosts running kmemleak and lockdep for a while. > > This time was different because I have decided to invstiage the code, > and found the deadlock. Still, no lockdep complain at all. I guess it's because kmemleak is quiet in general, unless problems are found, and lockdep never registered this combination - printk() called with the kmemleak_lock held. Thanks for investigating. -- Catalin