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Tue, 9 Mar 2021 22:39:49 +0000 Subject: Re: [PATCH v2 1/2] init/initramfs.c: allow asynchronous unpacking To: Linus Torvalds , Rasmus Villemoes Cc: Luis Chamberlain , Andrew Morton , Jessica Yu , Borislav Petkov , Jonathan Corbet , Greg Kroah-Hartman , Linux Kernel Mailing List , Nick Desaulniers References: <20210224142909.2092914-1-linux@rasmusvillemoes.dk> <20210309211700.2011017-1-linux@rasmusvillemoes.dk> <20210309211700.2011017-2-linux@rasmusvillemoes.dk> From: Rasmus Villemoes Message-ID: <9cf7863f-742b-1cfd-1027-04e314467e01@prevas.dk> Date: Tue, 9 Mar 2021 23:39:47 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [80.208.71.248] X-ClientProxiedBy: AM0PR02CA0126.eurprd02.prod.outlook.com (2603:10a6:20b:28c::23) To AM0PR10MB1874.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:208:3f::10) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.1.149] (80.208.71.248) by AM0PR02CA0126.eurprd02.prod.outlook.com (2603:10a6:20b:28c::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3912.18 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?QkRYQUl5ZVhuOXhYU3hlaUh4SW96Tkh2VHZnUTZlVVJrenJGQWlvSXczTW5T?= =?utf-8?B?MWllckZkT2NVemdjekJZUHpnSDNkSUdMK3poVGp2ZW82R0RNN0dEMUxvZGNZ?= =?utf-8?B?RzAyM05ueDIrYzk4dGZqdFJNa3k0Q1Q2bjAxRHM2aEQ1ZThIY05xaWpDNzh1?= =?utf-8?B?L2hRbWUwK0NEUUVnaG5QUGF2bm50a3ZoYWJwclRHOGNLZENXZzF0TjNkYWl2?= =?utf-8?B?VjFNUVJzOHJJZ2wyQnphb3MzNHZLOFlkZVpiU1hxRWhVSVc3a1N6bTB2ZkI0?= =?utf-8?B?V0cyZ01kRGJ3akZnU3RoTXFQdmhrVSs0aE9xOGUxQVhCR2E5eDBuK3JmNzdm?= =?utf-8?B?Mkh0alVRdTdDc1dVUmt1dW9lcWZiUGMvcEt3d0JQUlNsRHhSV0JWL1JuNEpJ?= =?utf-8?B?YTdDNVJKUll5WWQxeC9RTnFSRkNGK1BUbVBpa3ppTTljUnZGY0M1a1ZTL3FH?= =?utf-8?B?dVZqc2tEc09Xbkx4bnFVMVR1L1FabkppTjlseGVCYStKMk9VWXZsV3ZScE9P?= =?utf-8?B?UVR4K1hNeFhRd3c4Qnd5L2E0czhEZm1BbXZ1RFBzZjFaMTQ5bVhGNVVPVzk0?= =?utf-8?B?RVo3WGtjUWcyRjl3YkRQcjBSUzRmRER2bTZuSEFKa1owRmNZNmxYbWlGb1dq?= =?utf-8?B?MHRtNlBxTmFNK1IxRU1LZWtsWFhlbTR2Zyt2akhTTERzR0hGTU1uY0FkWXhR?= =?utf-8?B?em40UDI1MVdYY1cxUndOQ3hzV3BMTGVqdmFVWXVCaWlyUW82MmZnS1p1S05V?= =?utf-8?B?eFo2UGhCcUJndlJuaEgweTVDTS8zT2NlOHlGZnRwMzRhM05HM0RPWTA1S2dH?= =?utf-8?B?Z3B1cmc5eWREOEhCdVhqSzh3VkZtcGswak54NVhkWW1Uak9FcElYSi9CR3hw?= =?utf-8?B?T3RGL1d0K1dDY3JxWDF4N1Evb21QZ29UN1RWd2lmcXYyaW1NYUtydHFKSUFO?= =?utf-8?B?NHBtV3RhOE9QQzBkZmw4aU5aVzN4Y0pMUzEyWWhDSkhNWjRITi9WYVZJVmpE?= =?utf-8?B?N3YvN1BWNU1UaDdaN24yejlvZmc0aU1VdDhDUUREbWk3NnVSSXo1TEMyOFJa?= =?utf-8?B?SlFTdmR0YlhNSUR5UFIwZFhsbWNiRU43MGpiSEtqMzhhaWxUbUNraFRkQy9s?= =?utf-8?B?SFZFOXE4am5WdVpiT1MxcVF0RFcrZlRsUmZXTmswYVNTVENYWFBiQll0a0hu?= =?utf-8?B?ekNRcnUzMDFsNnp0OGw2SGZJYWNuV2RMenlCOUE1Y2UwaFhFUlA1YW5vdzJV?= =?utf-8?B?dEUrVnF1bitQWUZpbjNFc2c1bTIrenFaZHd1bmE1dFhIaDcvcWNqd1I5U2hN?= =?utf-8?B?NU5WaXF4ZTcrano3ZkJzYTI0ZHZ2UkFjVkNqOGJ3YkJqcHIyejhHd0t0a3M5?= =?utf-8?B?Y0VadWlZaTdGOTRnUDVSU0xNMUFlWVVqejV4R004REZVbFBuUGRPaUpleDV2?= =?utf-8?B?Uzc2djgvV29mbHlmU0dnMDl6S09XYUF4MHNnd1dna0dWdTdvTEkrS0xEM2RL?= =?utf-8?B?SC9rdUVpQW1XcHJnUEFFbkhHK1pSNlVtOGp1RU9QQUwvNXpqMjliQ3VZYXVC?= =?utf-8?B?SHFremQvRW1MMnErNk1aREY0RFpPdlhpajZTamtyc0laM1gwMC9od0cycmJB?= =?utf-8?B?VHhLNzJXbTVKL1VJOFlTQ1dyNGlsd3dKamwrcWtsYUJaU3NqS2xFN3k5Q2Zl?= =?utf-8?B?RnlFUVdNYTFocXVNTXc2bUdXM05xTEg3SkVKc0xWSGhHTGNaRm1RTFRNYXFT?= =?utf-8?Q?ljdAJiOoX9bn9gnfzJIHocNL1bePlbE9LuD1Caz?= X-OriginatorOrg: prevas.dk X-MS-Exchange-CrossTenant-Network-Message-Id: 99180e08-e74c-4ffe-c446-08d8e34c3f06 X-MS-Exchange-CrossTenant-AuthSource: AM0PR10MB1874.EURPRD10.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Mar 2021 22:39:49.8166 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: d350cf71-778d-4780-88f5-071a4cb1ed61 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: xWGFBMZS4n0oy6nCaJF/cPQdm5hCPip5MfocDMJ7B63wteebMLs8Re7nhq78lWFJrfFV1hCckD2GNS62xLnXmbNKRtwFamJuboyQHeFCNss= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM8PR10MB4241 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/03/2021 23.07, Linus Torvalds wrote: > On Tue, Mar 9, 2021 at 1:17 PM Rasmus Villemoes > wrote: >> >> So add an initramfs_async= kernel parameter, allowing the main init >> process to proceed to handling device_initcall()s without waiting for >> populate_rootfs() to finish. > > I like this smaller second version of the patch, but am wondering why > we even need the parameter. > > It sounds mostly like a "maybe I didn't think of all cases" thing - That's exactly what it is. > and one that will mean that this code will not see a lot of actual > test coverage.. Yeah, that's probably true. > And because of the lack of test coverage, I'd rather reverse the > meaning, and have the async case on by default (without even the > Kconfig option), and have the kernel command line purely as a "oops, > it's buggy, easy to ask people to test if this is what ails them". Well, I wasn't bold enough to make it "default y" by myself, but I can certainly do that and nuke the config option. > What *can* happen early boot outside of firmware loading and usermodehelpers? Well, that was what I tried to get people to tell me when I sent the first version as RFC, and also before that (https://lore.kernel.org/lkml/19574912-44b4-c1dc-44c3-67309968d465@rasmusvillemoes.dk/). That you can't think of anything suggests that I have covered the important cases - which does leave random drivers that poke around the filesystem on their own, but (a) it would probably be a good thing to have this flush those out and (b) there's the command line option to make it boot anyway. Rasmus