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 9861ECED240 for ; Tue, 18 Nov 2025 04:23:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CF6D88E0019; Mon, 17 Nov 2025 23:23:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CA7388E0002; Mon, 17 Nov 2025 23:23:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B96068E0019; Mon, 17 Nov 2025 23:23:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A53138E0002 for ; Mon, 17 Nov 2025 23:23:34 -0500 (EST) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 4E858C0351 for ; Tue, 18 Nov 2025 04:23:34 +0000 (UTC) X-FDA: 84122433948.06.BA2BD0D Received: from mail-ed1-f43.google.com (mail-ed1-f43.google.com [209.85.208.43]) by imf25.hostedemail.com (Postfix) with ESMTP id 67B75A000E for ; Tue, 18 Nov 2025 04:23:32 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=LNaVDu48; spf=pass (imf25.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.208.43 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=pass (policy=reject) header.from=soleen.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1763439812; 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=yHOZfK0pWU/GvMRSsb/xaHbV4r5va663wkrxdVP9VvY=; b=N9qVWFqt2ddvp/bwqjOeCtR9suRLs+hEGTU5ZlRJezaLQJG6aOITDdNkBjbMXuh11uxcir tHOtAeU7Yf8bYBVuYAT9Rr7lGUWDa2S5v1/uG9XqxeDoaVqHc/uy0iAxqfOdJYzmGb3X4H MAsoGf8kohmQOv0QjxCPZ8Au4RgBdOs= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=LNaVDu48; spf=pass (imf25.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.208.43 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=pass (policy=reject) header.from=soleen.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1763439812; a=rsa-sha256; cv=none; b=cKbmg9EItsHsN7plDOvG0RJ3+Snjmctp56HLiaNc4zJ11GVpCtHzJz7+faklOfBkYRJvtJ NwtHJ6OPjCwD2/LHt3CPwts80zzZlKKQ3HKgffD3aPLJBB8VFn6CJthYfYqDYErNIEhLor 54Ryo2cv/xXmEW6XV2jtQO/bHw8VOvU= Received: by mail-ed1-f43.google.com with SMTP id 4fb4d7f45d1cf-640aaa89697so6627875a12.3 for ; Mon, 17 Nov 2025 20:23:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; t=1763439811; x=1764044611; darn=kvack.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=yHOZfK0pWU/GvMRSsb/xaHbV4r5va663wkrxdVP9VvY=; b=LNaVDu48PKMxk1X5SQGzQUux9KEMxLRAp4AT0URgh9l2fCmly1IiMoEXsMijpCKNMH W4f/03rtvNcL0aYk2J6S39lnwgIoRjGXx5i7zNwyKNLmin5k1rSKjyoAQz58dJ+Bdgoc a/206c0ts3X2UAJxBxWhpxOe1yfwt9uDwQL/hGhueElbx8FFI5mTfAAB3V1es4q4Jkfe zS6JKSknniXwNSv/kiDGVWOy7VJ7Hx29wvVlMY+Zrk79V5jV9Aym4MiQRXNMhsa2hP5M 4oBOliQmfJKjBbSJKucNjZswTse+UBXMDBy17dUup5iEfOKH/RHbMQpeKRzYxhRoHkzQ wUnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763439811; x=1764044611; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=yHOZfK0pWU/GvMRSsb/xaHbV4r5va663wkrxdVP9VvY=; b=QV5iz728cOfVaEeVc+HG4N9g31biVFf+Mk/jo/A4Em8y8nDWglPom9ZW00Seo5s5fk SMxNxgnLi89l6Pe5KweF+ZxLgki+5spR9Pbqeklz7+iJkJaTAC5UcfgSizy61R538Fqn M5y42GMykj79iy6kpLMWK1ZgVEzT/4MmPwMpX/ZHFqOX4IMO2kN5FRoBXUvKfHajMcOQ gdOypn0cQpvd7/4of0NXnrRm9KOn2A8OHyr5QjyYweiY4bnWM68kw67L5yfaOgkwu65W YwG//iR/YZqJ4UzU2VAyXXADT1r+c5ywlqgLAb78JN4pJ1tQT8eFXfcBZpn5V1/nP+/j 8cCw== X-Forwarded-Encrypted: i=1; AJvYcCWYTZg5gu4Z4ImB9l2d1TsDg88SOIcFZc13H9aZfQFSdmUiSyBdNE/fP2BgRzlZV5IORdOq3U06lA==@kvack.org X-Gm-Message-State: AOJu0YyJ/+mtzceb8qKA/vQ//hzKqDYOSrh+8p4V3YSfN2N1hKevSwGX xNqLczjRfcOr/VeNkX47v43GniuRETatB1+ZJ9zAdfwrdOO+k8pC+mNa4y4gvrVRby4mggD6uNj pQYfbVPxln+Pdqbj/GOGLPOj3NOgikCJeE5t4/Y5QCA== X-Gm-Gg: ASbGnctlwc/e+G5cFTQ3LxewzYwBYmdoNAVsktYMvzeRG9EdoUsga3F/FFRSD57L4Hi fBwBaE2NekpYby+2XCB9/QvOSoP/UZ+snJDq863HDRY/jGBGlp/3R7MQobF/0LgWjHM9SpqSGyV YB34txeLdJGdDQ3OdMczcOipLaJlztLw/FVixiXyjDr11gibOOi5JOi+yn0kBoHP5Iwe6xNusQA OG/MMSU6DRcCuKI4WDLv1QU16H+lM+NUGxUh+4xq9Kw5hcJ2JHSUCKBAeam69Lf4sX2lcnd2SPv PHU= X-Google-Smtp-Source: AGHT+IHcXQAOPbW77p032BCA1yf03kdrt9TXEreALO4fe3G9Md4L5c16ZrMCE1/XunuQOVa5pqVrU/kpO2uPmj8xqWM= X-Received: by 2002:a05:6402:3508:b0:640:c849:cee3 with SMTP id 4fb4d7f45d1cf-64350ec18a5mr12648190a12.34.1763439810816; Mon, 17 Nov 2025 20:23:30 -0800 (PST) MIME-Version: 1.0 References: <20251115233409.768044-1-pasha.tatashin@soleen.com> <20251115233409.768044-3-pasha.tatashin@soleen.com> In-Reply-To: From: Pasha Tatashin Date: Mon, 17 Nov 2025 23:22:54 -0500 X-Gm-Features: AWmQ_bmu9XJ4F2q03zVpJ7QCWl2e5iEfuoUmDpvTnYNqaWiEdVtcHIOkeQ1NtZs Message-ID: Subject: Re: [PATCH v6 02/20] liveupdate: luo_core: integrate with KHO To: Mike Rapoport Cc: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 67B75A000E X-Stat-Signature: qwf8dfui8sseq6add59e3drjm9tczww1 X-Rspam-User: X-HE-Tag: 1763439812-783558 X-HE-Meta: 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 TLLfBlmg Zb6gh6HC46ARCCVyWK2lhS/4nhPwxVQrBbbnj85ovV3KZ2HSBm53puq8Awr++NUeasSbg//WbmDahmZkeCagZgoEqwPnGQioF6zpXUqlQqqLrp/cXbgmNlypS+uzX4K4nEcgJ2lA3+9B/u5090vAX0montcytrmePw3fD/ML1luWYBoajY8FWI0VxQtyzxYGKK8ihP8Ll2H52t3EfkHnMR/fFILYprwQ07BfpwDdpw0VPocAZ+Wxfjm42kw6i6jtqOv6S3eVAH58BoA0wONgqMAeLrYf3dOxpvLhmZXQenCK+8BK7Hq9ieXnxBTvn0TmJJT/UeWLdDL6j0Xs= 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: > You can avoid that complexity if you register the device with a different > fops, but that's technicality. > > Your point about treating the incoming FDT as an underlying resource that > failed to initialize makes sense, but nevertheless userspace needs a > reliable way to detect it and parsing dmesg is not something we should rely > on. I see two solutions: 1. LUO fails to retrieve the preserved data, the user gets informed by not finding /dev/liveupdate, and studying the dmesg for what has happened (in reality in fleets version mismatches should not be happening, those should be detected in quals). 2. Create a zombie device to return some errno on open, and still study dmesg to understand what really happened. I think that 1 is better Pasha