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 1FDCCCA0EE8 for ; Wed, 17 Sep 2025 07:02:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2D8498E0003; Wed, 17 Sep 2025 03:02:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2AF628E0001; Wed, 17 Sep 2025 03:02:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 179108E0003; Wed, 17 Sep 2025 03:02:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 02F468E0001 for ; Wed, 17 Sep 2025 03:02:52 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 6FC171DED34 for ; Wed, 17 Sep 2025 07:02:51 +0000 (UTC) X-FDA: 83897849742.20.C7E4F54 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) by imf12.hostedemail.com (Postfix) with ESMTP id EF52D4000B for ; Wed, 17 Sep 2025 07:02:46 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=Z+nNTHcm; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=YrNpBxUo; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf12.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; dmarc=pass (policy=reject) header.from=oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1758092568; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Jbnqip7ZcGxH5Zxqj0pCkyqFfltLpMxEADyq3mnFyaQ=; b=H/93A9nucCl/03Nj9ayqa0KX6ASNhxUort/df0mgqiZJ+T93q48PIMjEVieBP7UITEXC8U I/TrVOqzhT52lU+N6lU7D2JpEFECgJxz5c7tR6GSc7q1lBmRWdUtvKB71LKoQ3aLGOObZ+ 9zj7i7P3EJlr/MlnvEDFINTn3paL0tM= ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1758092568; a=rsa-sha256; cv=pass; b=kyMBsHl4bdMedxSWEcqJuFo3nvLnkCUwI2Qjiw0AEcpoLpRRdO+vMUaPKqsUlomnvKPP1p 1SYV/gNosRiu2y2q8g0rJaqOzEU41ssrQOXQTkxQkWWa6O6+JsYZo5KwoJS8av5u5U6w7q 6AXopIECjFHaZ7XdyEQ5uPGJvwWTZRU= ARC-Authentication-Results: i=2; imf12.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2025-04-25 header.b=Z+nNTHcm; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=YrNpBxUo; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf12.hostedemail.com: domain of harry.yoo@oracle.com designates 205.220.165.32 as permitted sender) smtp.mailfrom=harry.yoo@oracle.com; dmarc=pass (policy=reject) header.from=oracle.com Received: from pps.filterd (m0246629.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 58GLZH2Q032620; Wed, 17 Sep 2025 07:02:39 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=Jbnqip7ZcGxH5Zxqj0pCkyqFfltLpMxEADyq3mnFyaQ=; b= Z+nNTHcmLcpBVF8Bsj8xcDrCNKbi4CXmzkExtjKr1eexPPL4rVREu9UOOhbgJbxl v/Ex9Vxk5DmWU9XCmg4S2mGRs9jJ07x/yJ2yPOILozFSXodu/YNB1iLmQ2Y/tPdK vie7/db30XwFJEaJJc0cbzh2n3XPAaDVIMSymSeWomtRexYAlg807XIu8HBehIFp rrMUDjGfEIq9tr9lKg42OaiytPzrdFBFm4kCsPcMJWzre05Kht5FQBtDD2dnqrww D2M52fAYDAIRQn5LHud31aYWjsPMnvsz2hCt019+a1OhOxXYvax6cIL9x5zTnYmM nzOJEruKlDS2lrXz7k5NDg== Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.appoci.oracle.com [147.154.18.20]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 497fxb0hyv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Sep 2025 07:02:39 +0000 (GMT) Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 58H5vxKe035203; Wed, 17 Sep 2025 07:02:38 GMT Received: from cy7pr03cu001.outbound.protection.outlook.com (mail-westcentralusazon11010020.outbound.protection.outlook.com [40.93.198.20]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 494y2kp5c6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 17 Sep 2025 07:02:38 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MwzVu0vvyCGue4cmciT0fa8VVzVPUUHlBRcRhOVjhSK+hL05uc5W5Uemk+pFobeHBhoLKGFlBYkAIf1EQuacGyBuE5h1b6YYkVTqWdorxnlFhvVuOJokiBiEAG5Bacaq/Pf4exjEy6OoLDkN00L00w66pz3jrZgXAdmBbqBXpLGduCJQavUfd0vYpz8aU01OrA74W4u4CbhwvPhULkPUgeuUYZCkYbWf59Foux7Fjj86E3LksHIGFg1kcBsTcM3Ckt7ALZdpidOfRexMY1tOk7HePCTFXCSmrkXbSKXsiBIwMXuFIcXy1YZaU9HHfr9pYqrXzs9M5X9PVuFyibVpoQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=Jbnqip7ZcGxH5Zxqj0pCkyqFfltLpMxEADyq3mnFyaQ=; b=yGoSmfZishmYDeORrmDe3JYp1owLoISUvDHnyO2hP+/2HB+FfeoDvhhx8CFYSn8OjDrzp3SHcLG0pYzLhHPVISFTUWDdB64N8hADn/L8Dw2hNmstv5LsiS0vUOwMnAWcOraAFG5u13CGIfHWkc05NhJi3ezWzZXDLilr++/5o3cD8rVWG1g9ST6L+0/e0sukl9lrVQsYVv84iAu7a5Nb8mRl65sbRbXNNlX24Y0JaJtls0Ro8HqxD1/a5sUp1znspm7SOcJaJF3vAfapfPm6vnhxt29Fu3RVAEDwZZaIfl/BZX0QbwtZgc967/HmIi14pMp7rtkaZp4ccoCXQULXUA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Jbnqip7ZcGxH5Zxqj0pCkyqFfltLpMxEADyq3mnFyaQ=; b=YrNpBxUoenQ9M56EAXIcCkPOKCBUz9zoOqdx8Bt6IQIDGaygtwjmlIbXCZmk0N+cmERPa5nPRiL1qdTNUwbskTisOw7qy+AzOYMNjUK2RaregznJGcGwfVHEvaKqpxT4IMVbb/UFkb7hZRYljOq0mV39X/PGGeXkA/4TRBxbyIo= Received: from CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) by SJ5PPFCC6481C4C.namprd10.prod.outlook.com (2603:10b6:a0f:fc02::7cf) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9115.19; Wed, 17 Sep 2025 07:02:35 +0000 Received: from CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::f238:6143:104c:da23]) by CH3PR10MB7329.namprd10.prod.outlook.com ([fe80::f238:6143:104c:da23%7]) with mapi id 15.20.9115.018; Wed, 17 Sep 2025 07:02:34 +0000 Date: Wed, 17 Sep 2025 16:02:25 +0900 From: Harry Yoo To: Alexei Starovoitov Cc: Vlastimil Babka , bpf , linux-mm , Shakeel Butt , Michal Hocko , Sebastian Sewior , Andrii Nakryiko , Kumar Kartikeya Dwivedi , Andrew Morton , Peter Zijlstra , Steven Rostedt , Johannes Weiner Subject: Re: [PATCH slab] slab: Disallow kprobes in ___slab_alloc() Message-ID: References: <20250916022140.60269-1-alexei.starovoitov@gmail.com> <47aca3ca-a65b-4c0b-aaff-3a7bb6e484fe@suse.cz> <0beac436-1905-4542-aebe-92074aaea54f@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-ClientProxiedBy: SEWP216CA0046.KORP216.PROD.OUTLOOK.COM (2603:1096:101:2bd::8) To CH3PR10MB7329.namprd10.prod.outlook.com (2603:10b6:610:12c::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR10MB7329:EE_|SJ5PPFCC6481C4C:EE_ X-MS-Office365-Filtering-Correlation-Id: 20288838-513e-49d5-a20b-08ddf5b82d6c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|7416014|376014; X-Microsoft-Antispam-Message-Info: =?utf-8?B?VFJZaWRXNGtxcnBad0dVNTBublRRUmNIcExCTTgvM1p1bGdONzM3M1RNeERX?= =?utf-8?B?RmoxMmthaVJZdEtDa2d5b3h5TzBYd0hCTGY0azFaN3U2VW93aGdLYXRNdGxP?= =?utf-8?B?bjhEUmNmK3dZcDJRK0dwcGQ1QmpucU1tamFwUGJvcFU1WFYvQzg4NS8rUC9L?= =?utf-8?B?RGovMjRXcVY1V282T3k3Ynp6d2FnR2lodUV2VGlpbXFoSzR2bEdxVy9pMElH?= =?utf-8?B?bHFUR2FUaGdOekN1V05HVmVsbVl5TkZXRnFuY3JvWC9GbjNCUDZTUFovb2Q1?= =?utf-8?B?N2JDZ2tPYXJnNEY5MmdtYUluVWUzQUIxUTlxY3JPNDR5eHh3U1p5ak5LYzRw?= =?utf-8?B?bWRjR094RGR3bDJ6S0Nad3UvTDFsTEhzdkozSTR2SjN4azhvdVBTN2IrV2d6?= =?utf-8?B?dnRzVU9ZTHhsL3VwYTB1WWFNSHd0T2JsUDZuUkhVVzlHTVdVZ05pa3YxRm93?= =?utf-8?B?dS9lbXdUY3BsR2tua3pMYTNySVRpWlJIb3dySW40aGhFRk1nRTdpWTB2akdP?= =?utf-8?B?MlRBV2kycmkzcEY1eHc3UDR2Q080WE9Nd1k3SW9TcjVpV2c2V1U5L1lscVdy?= =?utf-8?B?MlNwS1VQd1pLRStLVGNQUFMwOHBsdm0wTEtyUVZ5ZTNwVG9EeUFjMHM0dnYz?= =?utf-8?B?cjhtYWxBUDFNMlFkczF6MU9wT241VnhBTm1vRnFLdmlTcWI0OWIzaExBZmJq?= =?utf-8?B?T0p2SkZYT0kyaVNjc1R5QzF5bXVyQUdXVjIrRHdScEtNTzQ1dGRpSFl2MWJx?= =?utf-8?B?eTd5RVNuQlNiY0hQeldtTXJaVmRWbUdZeFlhaTczZmxxd2hwUlY3aXlUV1Fr?= =?utf-8?B?UWtOMFgrRERLY2tSUHdaWjY4L0h0TkN2UTNPcmdubkdvcVRNQkxMeTlLV2Vv?= =?utf-8?B?ZGtOMUh5cDlmR1NnL0d6Z2NVandzelptQkFGTEJSTGFGR3hJV2ZKb2JYc3p0?= =?utf-8?B?TWQ4OGpqcEVvcE9leFNnbUxFVS9CMWFXeHpWVjZEMlFkYlZlUk0yRzJtTFUz?= =?utf-8?B?WCsyY1VKeU5xVXZiQzh6WUhYbUpGKzRvSi8wbkZFYXY2b0hlRHZHdUFBOE5E?= =?utf-8?B?czg1MFFQdnRPU0dxNE5NYTVtNG9Yb3RVd2lsR25wZ1EvSGxqZklwMVBTMFY0?= =?utf-8?B?dXdRalJLekpha0lYU0tPYU53TmloYWQ0S3o5UnJ4QkRwQlFaM0lWOTNqYTlC?= =?utf-8?B?dnVVVmVhZVlob0VPNHhHYUxqNXpSY2xCQzRhMWlRKy9oNm1sekk5cXpGZVdL?= =?utf-8?B?ZzN2bHduUzVnVkhUeUJwKzRTWk1IeHJFa05RWUxqYmFheUVLYzRIUW1uQlBG?= =?utf-8?B?RGt6SjVTYi9rTVVxOStaZzd0ZmZjcG1LREFOR3Vtc3k3dHlyK0ROQzBjMm82?= =?utf-8?B?TUdpbkNtVFNYM091R05ZWThkdFF3bStsc3RwajlQVGtrUWpWV1hBcnNlMlFv?= =?utf-8?B?ZUo5MWRUWWpQY1JHWGs3RFovUFBjVy8zQVl1STJPZWlNQUZ4SVlwV3hsd3l4?= =?utf-8?B?enUzT2h4bHkzZDhEdG1XaVlZeGVWZ0hyTHRldnM2YzBiVmwxQXN4SUZLQmo1?= =?utf-8?B?Kyt1djcvZ1BqQ0JkVzBZWkVDQksrNWpxWlR5MkhMNzk5eDdaNC9CN3RVbDN0?= =?utf-8?B?cklLMmRhQXNTbU04c296Z2ZXSW5iM1hRamI5ZHZHN0R6T0NhZnUxbE80N3Zw?= =?utf-8?B?cktuWlQ0U1RkQnQyQnIycmo0M1NyYktVdWl2WDJoVUtUemZEdnZ2dlljaVFT?= =?utf-8?B?SG5FU3JsUFp0dWdxdlNrZGxYMVJhN0VpRTBwaXYrVlFKRmpPdXhEWUpUQkhZ?= =?utf-8?B?SDg4R1JBUWVFOGZqSWczOWJYVUI2dzVSOGdCbHIra0hiendMT3E4Tms0SnZ1?= =?utf-8?B?Vmx1NHJOR3pzcFQyaGlsNGd2cVVTcDlYRXBMNnp0SjlZclJnUzBJV3Rha1dt?= =?utf-8?Q?1wYW6zZwmEA=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR10MB7329.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(7416014)(376014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?bk9qd01nZjdHL1pUeWZOUXlFdExwdmZ2QytwT3M0Unc1WFVKbEFJUzJSY2hM?= =?utf-8?B?L2xXdi9aM2dLUy9FVHFVUXU0RWRkUGw5NWJQSjM5ZUxpZW0yVVdPZGozQ3Nv?= =?utf-8?B?cEcyMnRJMm1saXdReGM2TWYvejJ6eW5mRmV0MzJrSmx3MHVNcVFiQ1RkMU10?= =?utf-8?B?ZWg4ZElBZzdoRUV5MzY4U21POGp6SXRnUzlCVkZiY1lodSt3UmxZbHhBK040?= =?utf-8?B?RHdLOGFQa0NqTTVnYTE2YTRseVNDb0gybUhNSnU0anFlQWx2dG90dTJDa0hv?= =?utf-8?B?QTkwTVA5eGwrbHNMQ1U0dGltUjJqTFJaRVczNmlMQTJHejc2SVhsMXZ5dlZR?= =?utf-8?B?RFpDNUN3bDhsZm1LbVdLckVCRDFGNzZOR3JFS0FtM24wbEN6eU1QbENmTXZX?= =?utf-8?B?dFlidlh5ZURhendTcnZDS1VDampWdTdSTUtGMzFEMU1wSE90dWhySlE2WlZG?= =?utf-8?B?ZXpvQkx4OFdwL2dvRTBYcUYrbTlSMEV1cDE0OW9DTWVMWmRBR3o3OUJwaVVJ?= =?utf-8?B?QlJDd0ltMjU4OFVpRmVIdWlNUFllT2VraFg0MFFUSWY5dExsd2dNYThlclJI?= =?utf-8?B?dDJKajk1dVgzenVPZ0ZnMGQ5M2RLTmJtZ3VnclgvZHF0SXh1cFMyaFRSMVdL?= =?utf-8?B?OTRpWThsYWhIMTN6bkpyMEtHQTNJR1EyMkJNYXhxbHprdUJScVhMREJ0THhH?= =?utf-8?B?N2JiOTFVQ3pzMnM5TzNqd3hUR2IvUFpZTEpJQ0VQcEdSai9DSFZJWHRwQzZF?= =?utf-8?B?YTNZYXEvL2pFZnZxQjlaZFFLSUgweThGNTVUU3RuamIySzhNaFB4RmZpQllp?= =?utf-8?B?cTBBd1k1SVA2dWdNeHA0UG1kMk9vaXFtdDVtNEdrUk5sZVhJUzFnZVRCWE1l?= =?utf-8?B?QVdXVFN3U2IzU01xamJZellWbk9mQUNKcmZRK2R6cHk4eXlucTdIMnl6UUtV?= =?utf-8?B?bEtobklOYlNPY2FEQXBocXNjMllGYkFTMUN2a3VzK2dTWmZLQ2ZTeXpNL1NZ?= =?utf-8?B?eXdROUxMOTc0cEtDeTVTYkVNaWN0ZUgwTk9SKzl1aURhV2MzZzFCby8zVW5J?= =?utf-8?B?ZU8vMTRQZTRVclQxSC9vWkpYUzJRTnIzL05tc3o5NWtQTW4weTNLS0tVNlJ6?= =?utf-8?B?clFUeEhZcDg3U3VCSHlaZzVNTGRJSlNVdUduTXR1ZFNTVCtnYXloSk9ESHJF?= =?utf-8?B?aGNXUVZzdElkNEpXcmQxUzVEMll1dGdoQXRMVjZhNkQ4blVldzZaUCsrUmNK?= =?utf-8?B?U3NLVjh2YUxWenlCMTBnd29Vd2RSNHRrUnZVSFprTmVhTUxCREE1ZThlNlJt?= =?utf-8?B?Q0VvNFRrc1JsaHhnMkVLdlFjbmRHSVk3bGt2WC8rUzhvbE9GZnJpR3paU1NJ?= =?utf-8?B?d0RUMjlsY1VpSUlCUnBFWXdNYXBEeVhkaitOUzJyR25VaVpRaUc4eTlaQjN1?= =?utf-8?B?MjZlQUNvTVE0MHAxMHg5U2VMTTdFTDFMbnFqci9MR3o3bWdXckgwMGx4aWM2?= =?utf-8?B?Y0R2MWFNNVVQN2pWbVdoYkM4bmlwSUdQUjF0V2NCZVZLNldhbUYwWlBxRWF6?= =?utf-8?B?WGl3KzFQOHlNVGhoT05xbDdEa2RHc3RIMDF0UVQ3cC9WQlI3M2xhRHJyK2Rp?= =?utf-8?B?NG8zNkR1aFRueFJMSGdORUc5a3RNVDU0ZWw2dko2STFxN0l4WDlvMFZXamdj?= =?utf-8?B?SUlNQ0JiUnZnQU03UWFCRXVRTThWYXdqZ1VWU1RMLzB0RE14NzVkN0ZRcENl?= =?utf-8?B?TmFxM1VCTVQ1YXdwUlhWVmRYMGhudzZMMXF4QmxsOGZVVE9BUGJybFA3aTV6?= =?utf-8?B?UUkxT2EraE5xR1dPSHlvdzJpUCsxZEpmVnQ1Z0tvc3JoNmtmZXgwTTZxdzJ5?= =?utf-8?B?V3YyU29BMmxKYlY3aGpFc3N6YlhmOFVzc00vTXg0dUNQbzhoYWI3R1NIWEQ3?= =?utf-8?B?Mm9nRjIwQ3ZjdHNET2M0M1UvUHpvLzByYmlnRERBemNGMzNBa08yQ01jNGhZ?= =?utf-8?B?TDNBZVI5KzVzaDdROEU2ZmI3YVI0UkJST2daZXdoWUNyVWdMNjZzeE5tQ2M2?= =?utf-8?B?MFZxTUd0MmdYOVEzRTdXcnNhNHZDYXdzSnZMejhiTEZkODlzVFhqUzYvSTV5?= =?utf-8?Q?7XgS0gBVZPt0WLkXO8QLjWUMO?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 20288838-513e-49d5-a20b-08ddf5b82d6c X-MS-Exchange-CrossTenant-AuthSource: CH3PR10MB7329.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Sep 2025 07:02:34.3908 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: GTln2DYITTfaDvXtZA9jmvs9cOYBZIIWkKwDMa9JS0xeyTNsKii0di6igBDqVKcx4P0dYeQS3t0wnuFU6l651Q== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ5PPFCC6481C4C X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1117,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-09-16_02,2025-09-16_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 malwarescore=0 mlxscore=0 adultscore=0 bulkscore=0 suspectscore=0 mlxlogscore=928 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2508110000 definitions=main-2509170066 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwOTE2MDIwMiBTYWx0ZWRfX0oijGDI2Zu1E sf6rUV28btzlr7NYtUGr3ZYvZshav07+v1FgPhVY6o89zk+s3DbZ9V7lBdrsaIpFstEz+SNMy8I mya0OrVd1uLgAKzOKJJDoEwH31qvXT08yVZQCkxIbKjoSnTPaGEB2fSntzDeuLg9me08CIm0Rmc gm1Q0os49isvW4xdh2fXJI7PfWQ2vMQUQbLDLb9AW31p8KsUA627zif+h2v71Mr5EG2u1eAv7SE k7KaTuiom6M286aledlohiaxyOl2Rx5yNHGAw/NHvMIV7ecLSAfJcSsMmmzXyP3M+utBKVsWLO4 peQOyR0wSf5aM/mC1ofey2VQWb4UjgVUt+XNTqbsOKzT4yJnn8F2dFRnulex7Xgfj9YnTeh31Tq Qd5erAc/Z4967acmuDFpVwr6DmMDug== X-Authority-Analysis: v=2.4 cv=KOJaDEFo c=1 sm=1 tr=0 ts=68ca5d0f b=1 cx=c_pps a=e1sVV491RgrpLwSTMOnk8w==:117 a=e1sVV491RgrpLwSTMOnk8w==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=yJojWOMRYYMA:10 a=GoEa3M9JfhUA:10 a=4pYPNrIQVuUIRFadlSAA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 cc=ntf awl=host:13614 X-Proofpoint-GUID: Y_B1m0hEH6OW88Xnfr-R5kx6wiluyN7e X-Proofpoint-ORIG-GUID: Y_B1m0hEH6OW88Xnfr-R5kx6wiluyN7e X-Stat-Signature: py3xubxmkbnek31zncfcuecqdqyy8uws X-Rspamd-Queue-Id: EF52D4000B X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1758092566-487183 X-HE-Meta: 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 icCH52i+ LmRAHS4gy7H0UNYs1gXeDCgIf+NMT4CtYVLJG1puil2Tift4zzvBL9P8JfuPZSYvV9QnbO/2IRuNkI6LySURyij5t6mWFmBM9U/7JufDgRLnC+xoLTGrq7BkZnz/joZpT67A25GB8oYsI8xBXcHjBfNfQA7zoGzRbHpmduAt5ZxG/8ZwNvnqpq4Zh+JjaVhsWP4RV 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 Tue, Sep 16, 2025 at 01:26:53PM -0700, Alexei Starovoitov wrote: > On Tue, Sep 16, 2025 at 12:06 PM Vlastimil Babka wrote: > > > > >> > > >> Hm I see. I wrongly reasoned as if NOKPROBE_SYMBOL(___slab_alloc) covers the > > >> whole scope of ___slab_alloc() but that's not the case. Thanks for clearin > > >> that up. > > > > > > hmm. NOKPROBE_SYMBOL(___slab_alloc) covers the whole function. > > > It disallows kprobes anywhere within the body, > > > but it doesn't make it 'notrace', so tracing the first nop5 > > > is still ok. > > > > Yeah by "scope" I meant also whatever that function calls, i.e. the spinlock > > operations you mentioned (local_lock_irqsave()). That's not part of the > > ___slab_alloc() body so you're right we have not eliminated it. > > Ahh. Yes. All functions that ___slab_alloc() calls > are not affected and it's ok. > There are no calls in the middle freelist update. Gotcha! I'm confused about this too :) > > >> But with nmi that's variant of #1 of that comment. > > >> > > >> Like for ___slab_alloc() we need to prevent #2 with no nmi? > > >> example on !RT: > > >> > > >> kmalloc() -> ___slab_alloc() -> irqsave -> tracepoint/kprobe -> bpf -> > > >> kfree_nolock() -> do_slab_free() > > >> > > >> in_nmi() || !USE_LOCKLESS_FAST_PATH() > > >> false || false, we proceed, no checking of local_lock_is_locked() > > >> > > >> if (USE_LOCKLESS_FAST_PATH()) { - true (!RT) > > >> -> __update_cpu_freelist_fast() > > >> > > >> Am I missing something? > > > > > > It's ok to call __update_cpu_freelist_fast(). It won't break anything. > > > Because only nmi can make this cpu to be in the middle of freelist update. > > > > You're right, freeing uses the "slowpath" (local_lock protected instead of > > cmpxchg16b) c->freelist manipulation only on RT. So we can't preempt it with > > a kprobe on !RT because it doesn't exist there at all. Right. > > The only one is in ___slab_alloc() and that's covered. Right. and this is a question not relevant to reentrant kmalloc: On PREEMPT_RT, disabling fastpath in the alloc path makes sense because both paths updates c->freelist, but in the free path, by disabling the lockless fastpath, what are we protecting against? the free fastpath updates c->freelist but not slab->freelist, and the free slowpath updates slab->freelist but not c->freelist? I failed to imagine how things can go wrong if we enable the lockless fastpath in the free path. -- Cheers, Harry / Hyeonggon