From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f181.google.com (mail-pl1-f181.google.com [209.85.214.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3821C323D; Tue, 22 Jul 2025 00:29:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753144145; cv=none; b=W7BPF+YiPvmfr+1fDOBi+D5u2oGqR3ScGUKcJrQHG97CUixGuK8csrQPWuWbErbTqA364gAhdc0fKSS03kaznKJkoUDaA3A/lvBMWhaO2Tta8zztCKdfYZh/wJXY0Cra5m/vdAwwGpl02aeVmT7h9rN0tH5p14WfaOoHQ3n45C0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753144145; c=relaxed/simple; bh=1oSCdNX7DQYIk3n3ZJ1VeGj/LdIxW93xsqtNV72FQrg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=I8zJlPo1IbOFJo21NBgv0x9Naf0BOwxZH3dTuS/3axS1GBCoFTkCO12N1uAb22P/LDxhQSt9xRLZKWhmBwwXUY4Imz70HSqXxZfuzucKqRiC3OTc35Q4nAdI+VzzhABpQkAF/mJCMayiGafkZK06VbZgo5y/4TWoqARI/0u1HDU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=LsLz5ND2; arc=none smtp.client-ip=209.85.214.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="LsLz5ND2" Received: by mail-pl1-f181.google.com with SMTP id d9443c01a7336-23aeac7d77aso41110845ad.3; Mon, 21 Jul 2025 17:29:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1753144143; x=1753748943; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=oq4jdal9TquQDBj2libt0/0yRkNmtdQsAFlZRWxtTdo=; b=LsLz5ND2jMQtkHZK0g/hNw71qQpwa7L9nxm/Qf0pCktCIERgLjLP1wP6o4CT77u5nj 6po2RAVyVSQEhSrMrckBztjtPaYk1gNEC2/KdznHRs1NGzP/dA9kgpRwjKv4uiWVCxoX KVO8LU1sVOdk3Y+LjH1Pqna9+YSFeaEZ3yPG9g7xqp5waKiXeUCimI/lAs702zDCfYPx Bf1PiD28p+VijlE9r6R1qgGdhSYw2fSq4CmiVNBVlkV3aHpK4QSD8fJcOSmye4vQsaSj dp1wSz0x/ljwcMg24LsLYdnI+ZuO2ba2sM/5/olElB143BI6MHVnJg2kKgIocDzyMBSB s7jQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1753144143; x=1753748943; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=oq4jdal9TquQDBj2libt0/0yRkNmtdQsAFlZRWxtTdo=; b=ef/L/Ld+sKFwUPgjFmxDSk3rUv5i/CgSYS4Mxu3N7g34KV0afYOb2+bTvMRd1ZtWLd MdqyEBZ7ICBXrjAFHN1zZJrxW6IMVkQquTILxJiTyUAoD34rKpGpUTFnpdd1lC0sUirq zEldtNXiw0yguzdIbBhIg+KM3BsBh2Vc8s5QbzsC0OfYxjoDmP8uPEwP1Ngz/r6Yj1uD PTPWkzuYAfqhL+B/xzHR5OziMNN8c5BTc4+848nIuVgnQIGmB8gnxQGB4rrKG3dB651g +5Q0I/hX3fjx7XsO5gonv221Pjrj0jfGVASCNpcGWSQgSbO4+3Sqda7d+f5Ph+bEmNM9 zlkQ== X-Forwarded-Encrypted: i=1; AJvYcCUPQaM/beLBEUZ7pveqJX3YbYDVivDjKP1TBpUfMQ5YnQvXArlPGBrI+I0wJxJIhNDJii8AzFwFuD0DNbaG@vger.kernel.org, AJvYcCWt0KY08m6OIoYUqLkc+UccoO9zFcdeVw0SNYwtklzgy3kNcSUr/xrQCTS31SNlzlPhwj8okXKR@vger.kernel.org X-Gm-Message-State: AOJu0YwvRjTOFsn2noua8dpf/oIwGb9cTDsn6PlhMWmptNmmWnEuGlZm UIw0G5OqtMI2X+ta4Z9eLAm3vyAZoA9YIq+9sibmo/1zuE0Q73bRsooS X-Gm-Gg: ASbGncs2nc2YnlKbG4dShctsgUAQMJHPPrlPcI3lh45ExcVhmW9HYZfo8O9Cs2mthkX TE3kkNoIgPQTPlll0DvNOFOXNU3z7Sd1+9NT8v23BGbw5MrvOUsekxjfn/tzDDU05Xio+Z2O5TQ bwEzFAHj42XUJc5317dgug4r0pUtL1aMbpUH8N7CR8AFoRcQ2CmH2DSj75sHzIeJJdcBGL03NP8 2H9H9NtYX+J/k1jtkNLLIj61yWWXE2+05K3pdiiV+U+Hquv6uofZkez3rboLdMmAKuijN7lbrEA efQ9rL/+/7SHbK6CKCl3NtFn+YwUKbVQ/K6+AdFodZAbNARMgtqM08uw1r0yoYqLDHCNBy5ZJYb NgBbR6bSKEo74aNrvHOz1LUrue/do9Kg= X-Google-Smtp-Source: AGHT+IHNF7BKZ99z9zCYMqDZ4VD0vwvR9MiC03EI2F3fyhR2Q0qcVIHpxTmg4IiArxwEH3HbEViX9A== X-Received: by 2002:a17:902:e804:b0:235:f632:a4d5 with SMTP id d9443c01a7336-23e24f363b1mr274426545ad.9.1753144143405; Mon, 21 Jul 2025 17:29:03 -0700 (PDT) Received: from [192.168.1.117] ([73.222.117.172]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-23e3b6d672asm63820045ad.178.2025.07.21.17.29.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 21 Jul 2025 17:29:02 -0700 (PDT) Message-ID: Date: Mon, 21 Jul 2025 17:29:01 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [cgroups?] WARNING in css_rstat_exit To: Shakeel Butt , =?UTF-8?Q?Michal_Koutn=C3=BD?= Cc: syzbot , cgroups@vger.kernel.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tj@kernel.org References: <6874b1d8.a70a0220.3b380f.0051.GAE@google.com> <2b10ba94-7113-4b27-80bb-fd4ef7508fda@gmail.com> Content-Language: en-US From: JP Kobryn In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Thanks Michal and Shakeel for the input on this. I will be sending out a series to harden css_create(). I was able to open a small window for the placement of css_rstat_init() that satisfies existing constraints and allows for error handling before refcounts come into play. On 7/17/25 11:46 AM, Shakeel Butt wrote: > On Thu, Jul 17, 2025 at 03:28:27PM +0200, Michal Koutný wrote: >> Thanks for looking into this JP. >> You seem to tracked down the cause with uncleaned rstat, beware that the >> approach in the patch would leave reference imbalance after >> init_and_link_css() though. > > Yeah I discussed the same with JP and I think JP is planning to move the > css_rstat_init() before init_and_link_css() and a second param to > css_rstat_init() to differentiate between css_is_self() or not.