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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5777DC44536 for ; Wed, 21 Jan 2026 14:58:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 91FEC6B0088; Wed, 21 Jan 2026 09:58:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8CA236B0089; Wed, 21 Jan 2026 09:58:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 790146B008A; Wed, 21 Jan 2026 09:58:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 639426B0088 for ; Wed, 21 Jan 2026 09:58:47 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 1441016052D for ; Wed, 21 Jan 2026 14:58:47 +0000 (UTC) X-FDA: 84356277894.19.E9569BF Received: from mail-qv1-f54.google.com (mail-qv1-f54.google.com [209.85.219.54]) by imf18.hostedemail.com (Postfix) with ESMTP id E2D4A1C0007 for ; Wed, 21 Jan 2026 14:58:44 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=cmpxchg.org header.s=google header.b=B9Zr8P0p; dmarc=pass (policy=none) header.from=cmpxchg.org; spf=pass (imf18.hostedemail.com: domain of hannes@cmpxchg.org designates 209.85.219.54 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1769007525; 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:dkim-signature; bh=11H3Sl0B2LnnaUo00s74ciXm10QbO4phXHCmMu1QEis=; b=vQmKLCk5Wmm3noZNE/2bPIKVuEz8fRHkpEDzp6oQ+LEy5+Uxt0o82AZpdkzWpA9Iczdo4Q /3IpUfGfzH3JbIvU6MYP9hQH8Kqu7r2Go+XNnQBXa0iJfEatktGnukzzbtKjIywTKwVHVb DSKaGm30kfz7S7xCtb/tknUiUJ3JP4c= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1769007525; a=rsa-sha256; cv=none; b=24q2Px3W9+92BJhDd6/Dd6oVfQ8dEPrakSZPfRxsf3HGs/UA9aGhB6SoqnAJaJm0TVJoxs VXGdsQuH1VCuDVYvkp8sCLEUDhzDAgrjihj0tvYEzvoA9x6u9OwMaTDC5PfQmwGaUM83Qm 1K7oGjlJnvgfPmruPpXGSoQuNz17PUc= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=cmpxchg.org header.s=google header.b=B9Zr8P0p; dmarc=pass (policy=none) header.from=cmpxchg.org; spf=pass (imf18.hostedemail.com: domain of hannes@cmpxchg.org designates 209.85.219.54 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org Received: by mail-qv1-f54.google.com with SMTP id 6a1803df08f44-88ffcb14e11so87904846d6.0 for ; Wed, 21 Jan 2026 06:58:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg.org; s=google; t=1769007524; x=1769612324; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=11H3Sl0B2LnnaUo00s74ciXm10QbO4phXHCmMu1QEis=; b=B9Zr8P0pgzDjTanRYDIc0YdQmDp0ANG9rQ54AzHYiqqizkmpFQZOGfTjoKVVxfuVdj o/mK3/WqXoZHz87/b5ZwRDnVUy5CUGRcz1f1JG/VLk2PF81xpUUfOJH6zRD2/Aw8JexW Njo3z7FnBJsYwfzpxKhvcBHi7UfXb8T4YByBo+a6UeSUllVhmtt/XvO+8TLH8RFkBNNQ bBbxgP7FlPOlpKaX+WS/7JVZkrBm8Y/GRMBOoK8k15vv7rpnlHmz0tuXf40UOBxzha75 tc25oznn2xSJSW1VPjl+cd2whxK4ngpxmfeBjiGWi0/vCc7yk1tCqxubuLHvgXa+1CdC 9WTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769007524; x=1769612324; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=11H3Sl0B2LnnaUo00s74ciXm10QbO4phXHCmMu1QEis=; b=wsegKWig0cV6NxDrK592JwfN9zdQumRys0aXHwLGy6l7fDEhZ98oAEWhNWErN/RwPv Vh8c2hOGymQW69cWaNMbVvnnCXqcRXgO1PZWeCENF5owc7ytcsOa7oYyDFdQ1KGAQXCo Wiu7BpTHPc6U5Tp2LB4c46E5CSepmeFKxwXc+iW8XpBZK8dv8cwNl6mFvK/JHK12NxXe nFjvrbD/FV5L90uAc5BWsQ5soQuMCYvgpUlDWr3mbXFuh78iU0FdvM+kmh2U/IHGaUf3 CZnRjCpNNfSrVU4ZzJ8Bx/FHfZcKhS0dCcFlD4vuzZCO2lST6E5NVd7p4J/eMXY23CjN DDjQ== X-Forwarded-Encrypted: i=1; AJvYcCXcKR8pkDjgpzuJ8YFSn8+ShJzvb+7sLgAq7tEqYgjYarqcMq4O3u7mCHvH2uXxZjn0FY3947Lr2g==@kvack.org X-Gm-Message-State: AOJu0YwkNj+FyVF8yMB6lMbeon2fvYHoI7y2jYo8fwFY+9Jzt+TW3Zes QgI8ju7BPUElWFh1ljpfJD70mGoXR8fpoxd7VxWmdg87Yp4MaSn3SfsQpCYI5phmrjc= X-Gm-Gg: AZuq6aJHJSXk3dlMPkCQ6O/9e9sE6knHEdYP8DrNfHmiJhD5QobSmg7ceijv0abH92/ PHU5lNl6lkOdlHBRbdXMA9PSg7Q/ThOuCV2GTSUh3whwbcjW9cqr4bgJrtFytYlW8YDx0VTS27g 525UqtHYYiyGC1TjpGEb7jC1/iKoGOk3yFx3PALS7pdVVAI2WOsaWzS/V30bSEqho9mOPdUbm8I H3G/xq/bq35waQ0Gha/bMD4LrZPil+IxttUNct50vFHXe4WXhqRmOE4Mm1f/PPd+OEhnb6ta1ya rql+CYbixXIjSqv5nRfYn59DZu1RR1Ghcvl719+mwJoV6NRSb74OPEGXhXEJND2xSrk3HrxdqR5 9t6e2OQieB86S1DmWt6CZfwn+HFpGh3B+t+QXPpKn7APjQsAS05xZptSqQ+kPA+bh50P+FEn0Xv XBXdQDL9hPhw== X-Received: by 2002:a05:6214:400c:b0:888:498e:5a3a with SMTP id 6a1803df08f44-89463d16ca5mr80297446d6.68.1769007523747; Wed, 21 Jan 2026 06:58:43 -0800 (PST) Received: from localhost ([2603:7000:c01:2716:365a:60ff:fe62:ff29]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8942e6c9a9dsm132520486d6.43.2026.01.21.06.58.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Jan 2026 06:58:42 -0800 (PST) Date: Wed, 21 Jan 2026 09:58:42 -0500 From: Johannes Weiner To: Andrew Morton Cc: Deepanshu Kartikey , syzbot , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, syzkaller-bugs@googlegroups.com, Muchun Song , Minchan Kim , Kairui Song Subject: Re: [syzbot] [cgroups?] [mm?] WARNING in memcg1_swapout Message-ID: References: <696b56b1.050a0220.3390f1.0007.GAE@google.com> <20260117165722.6dc25d72fd58254cb89e711b@linux-foundation.org> <20260118125311.e1894f598e2a8ef626f47f25@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260118125311.e1894f598e2a8ef626f47f25@linux-foundation.org> X-Stat-Signature: uo5bwos6je1mq79pdwpzeonzm7n38twg X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: E2D4A1C0007 X-Rspam-User: X-HE-Tag: 1769007524-831125 X-HE-Meta: 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 cHR0xs+j rVOPAKWwccH4Ef6MVeBTGNUlIKPbwBa50iWcRtADRI+9RLuCVhfTbnaZ4u7RGMUSyNEUvvclDdj8lRdUAdPk5hvjSI50DQHSMeOxB8bRGkMqHF/wUsu1/GcbkIwhPKoiM7yFvW5yYlkHxxEX9Skkdfjp6jwoIFedJc6GJVJ4rZuwlvzfoM5TgelrM8htQYuC81sSAwRdxq1AUcGV+yTAs9K9WmWHUG7Ee9UwS+UgZu34+UXNnwi0SyGcZF3waApyehnVAHbaFBphycUAj9UOpu4QaxeEbsASIeqP1X33Mp+kDyZPmiLhsjFow3TBwH8M0aoshWU4GeKUqZu3yPzVVaePqt6Q6pc0W3Kk218iOslz+V45kgqn4e0sXmEPWIw7rUhH0iBuxpWOWYiOzMNQPeF044M4tVQO+czxKkkd9CdCy3k7nPq/GShX0lyAN6UjC8c1pMmhegsGrQ7T3HtgoHrVjGW7mAAMSkbNhGN0j6BSuo31dvKEmoSBrc4rzBdAepOOoit8s+tim5j0gUGu+i9QEWiAWEPCGMi1/xtocmpiZJlsqbl+i/k4lqXVfRU+EfoyRNJkL7zBEKgYn7fioFBRFesL7djK09/QTCCKQKFE0H6aIq+i4FPARCXXkTLNWpSSAi+lnj8PP/ZA= 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 Sun, Jan 18, 2026 at 12:53:11PM -0800, Andrew Morton wrote: > On Sun, 18 Jan 2026 12:31:43 +0530 Deepanshu Kartikey wrote: > > > > > > > > > That's > > > > > > > > VM_WARN_ON_ONCE(oldid != 0); > > > > > > > > which was added by Deepanshu's "mm/swap_cgroup: fix kernel BUG in > > > > swap_cgroup_record". > > > > > > > > This patch has Fixes: 1a4e58cce84e ("mm: introduce MADV_PAGEOUT"), > > > > which is six years old. For some reason it has no cc:stable. > > > > > > > > Deepanshu's patch has no reviews. > > > > > > > > So can I please do the memcg maintainer summoning dance here? We have a > > > > repeatable BUG happening in mainline Linux. > > > > > > > > > > Hi Andrew, > > > > > > I checked the git blame output for commit 0f853ca2a798: > > > > > > Line 763: memcg1_swapout(folio, swap); > > > Line 764: __swap_cache_del_folio(ci, folio, swap, shadow); > > > (d7a7b2f91f36b - Kairui Song, 2026-01-13 02:33:36 +0800) > > > > > > Kairui's reordering patch appears to have been merged on Jan 13. > > Eek, there are many patches, it helps to identify them carefully. > > I think you're referring to > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-use-swap-cache-as-the-swap-in-synchronize-layer-fix.patch This was supposed to be the replacement for Deepanshu's patch below. > > > The syzbot report is also from Jan 13, likely from earlier in the > > > day before the reordering patch was merged. > > > > > > So this report is from before the fix. The warning should not appear > > > in linux-next builds after Jan 13. > > > > > > Thanks, > > > > > > Deepanshu > > > > Hi Andrew, > > > > I tested with the latest linux-next in sysbot. It is working fine > > Great, thanks. But we still don't have review for this one. IOW, this is not necessary anymore. Kairui's (cc'd) fix which you picked up fixed the syzbot reported problem. > For some reason I don't have cc:stable on this - could people > make a recommendation? So this: > From: Deepanshu Kartikey > Subject: mm/swap_cgroup: fix kernel BUG in swap_cgroup_record can be dropped. Please correct if I'm wrong.