From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f179.google.com (mail-pf1-f179.google.com [209.85.210.179]) (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 813B23208 for ; Tue, 7 Oct 2025 06:32:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759818754; cv=none; b=GsGG5tapBLf03AXwY+Q8QDoMhwJYqJzpSxPzcyl+0C7eJR+p/9uT1KZ0i9MvaIyhFvOcidPMFZB3vTUAEYx6mWdFlC/fB8m4Eu9/S1wQel4l9mu6KOsKJT44MULWwBwlQRUBLuEfMjKHgaj+uIlfGvXBi5l0cxtovoPIq+hLFcE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759818754; c=relaxed/simple; bh=hYyfYckrsx8MnB/o9ezaFvNJQCYjBKMqokG3tB5c0LU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=U9y6Ri85TzyhF71UtzBn3885XJhjO1vMjA6+LllKNx5a9lgOXnkiMQjbaCYMLKKMqECz3ACAI1onAyxUQnTqGtDCK0ahdmGcaqFFRbpoqIuD46s7ryn2d4AyN0UH8T30QTxnUgmaYrhLUHV6lCPIEdae+2ratKVtQddHgHRmAZ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kzalloc.com; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.210.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kzalloc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-pf1-f179.google.com with SMTP id d2e1a72fcca58-781254d146eso397346b3a.1 for ; Mon, 06 Oct 2025 23:32:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759818752; x=1760423552; h=content-transfer-encoding:in-reply-to:organization: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=KJGCKWDOB+HDW2IfjXMw+O6nf5o51khcjA2mbC8osTg=; b=jvjEP4GRSnEYo01o+KA5ocBo+iYLmBiLZyD6Q5sRXgOEa0nTntHDr99ZW8zi0iPVT2 Ql43YwbcLoy/B2v4G7W+jPkMW2GkSPO93xWuGhCJYowtXmZkku5+t3DSfwJIg6efERcI lyeqKd2qAoOLaHkcHKNcJcIVCH7IG01Vckzk06RuRS7/5/GX8RETT8O+HJMe+0z3CJ++ WR+g3+mSmDBHNCO3/RMkf0b839f7OXRQ3z6imaSjlySd/OBzYRT+xLQExs89CPaBfb3I 03BxBuFEjRpqPQa6FxZOn6K3hfIJ0Q/772mpNuQjKd0sw2ER9cH9wOCRIV0UcJzwMcoH 20Fg== X-Forwarded-Encrypted: i=1; AJvYcCXP9m4bfHEU2iSiP5v3Y9a4JlNebjmDwtrqdH4a+EVSCHc20rzo1EFCMt9IoKD/VvvwfrlWEfzsKoYUXlE=@vger.kernel.org X-Gm-Message-State: AOJu0YxMpAMGQNSYeEeEHkHNE3wKTmSAeyCxgt6QfHiJf6a6vdj2Qc6z +TuAkyDsdDtBxUNoEvJgQHWq9avTzhuEu8o3thZOSSTI2KWsv6MjpOkF X-Gm-Gg: ASbGncsnjZweGKaQNkoZxflD86Eiv0MoTg51Dg8a6FPcmce9+FDfOFCkEJv/ZX0gZ6Q VAsDh6ggBOl+uO1e4uEJjFh67PvK4CjWOsOni7kxYZb3/x8eB+mpSt5AxAUgGi/09YWhX07pk/i 77C7HfQbBNxpnNmtUbxRm774FrGCiweRxxuOJJfM/7naozd/cTYoyF81BRU8vxck0LuaGpNfT6l sHJ9OuQ1nQeHr5nilzHKdbAsoGuQAGSH+R40SBVcgc8PvLRm2LTNyITe3DZpyclJAPqBxswn4ZW ozTHUdKRH7Y8IoJ6dwZgj3zP5zuGr8hIwsz+OZDw5vykMHD1NdOEcJU2EpjcMco7+sZHOPEUe43 uildTQ2djywS7WgCOHkvZRgaUdLRJtsooJeSR3sMl1seX02DIT6bS2RQFwqvc9cb1wJioUnoneX 1RYJ0iQihH6vevsq9rJRmwmOKqp/VN/pTxlg7wAmTvmDsMw4YmVRSR X-Google-Smtp-Source: AGHT+IEhca/DKV1gkMLzYSeFHCblQernrwx8MiefUNdEs8Uem/33USeoThMFjQF25dXOu6Ao9GH78Q== X-Received: by 2002:a17:902:c403:b0:27e:f02a:b280 with SMTP id d9443c01a7336-28e9a65bd1cmr98147365ad.5.1759818751599; Mon, 06 Oct 2025 23:32:31 -0700 (PDT) Received: from [192.168.50.136] ([118.32.98.101]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-28e8d110cdfsm153463955ad.13.2025.10.06.23.32.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 06 Oct 2025 23:32:31 -0700 (PDT) Message-ID: <3b66d603-543d-4616-92a5-9e6e32f116be@kzalloc.com> Date: Tue, 7 Oct 2025 15:32:27 +0900 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: [RFC] mm/migrate: make sure folio_unlock() before folio_wait_writeback() To: Byungchul Park , Hillf Danton Cc: David Hildenbrand , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel_team@skhynix.com, Yeoreum Yun References: <20251002081612.53281-1-byungchul@sk.com> <20251002220211.8009-1-hdanton@sina.com> <20251003004828.GA75385@system.software.com> <20251003005230.GB75385@system.software.com> Content-Language: en-US From: Yunseong Kim Organization: kzalloc In-Reply-To: <20251003005230.GB75385@system.software.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Hillf, Here are the syzlang and kernel log, and you can also find the gist snippet in the body of the first RFC mail: https://gist.github.com/kzall0c/a6091bb2fd536865ca9aabfd017a1fc5 I am reviewing this issue again on the v6.17, The issue is always reproducible, usually occurring within about 10k attempts with the 8 procs. On 10/3/25 9:52 AM, Byungchul Park wrote: > On Fri, Oct 03, 2025 at 09:48:28AM +0900, Byungchul Park wrote: >> On Fri, Oct 03, 2025 at 06:02:10AM +0800, Hillf Danton wrote: >>> On Thu, 2 Oct 2025 13:38:59 +0200 David Hildenbrand wrote: >>>> >>>> If it's a real issue, I wonder if a trylock on the writeback path could >>>> be an option. >>>> >>> Given Thanks to Yunseong for reporting the issue, testing, and confirming if >>> this patch can resolve the issue, could you share your reproducer with >>> reviewers Byungchul? >> >> Sure. Yunseong told me it's 100% reproducable. Yunseong, can you help >> him reproduce the issue, please? > > +to ysk@kzalloc.com > >> >> Byungchul > Thank you! Yunseong