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client-ip=165.204.84.17; helo=SATLEXMB04.amd.com; pr=C Received: from SATLEXMB04.amd.com (165.204.84.17) by CH3PEPF0000000B.mail.protection.outlook.com (10.167.244.38) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.20.8511.15 via Frontend Transport; Thu, 6 Mar 2025 15:26:40 +0000 Received: from [172.31.188.187] (10.180.168.240) by SATLEXMB04.amd.com (10.181.40.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Thu, 6 Mar 2025 09:26:35 -0600 Message-ID: <1c4b7bb2-2b2c-472f-b392-ac75cf482ec0@amd.com> Date: Thu, 6 Mar 2025 20:56:32 +0530 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 PATCH 1/3] fs/pipe: Limit the slots in pipe_resize_ring() To: Oleg Nesterov CC: Linus Torvalds , Miklos Szeredi , Alexander Viro , "Christian Brauner" , Andrew Morton , "Hugh Dickins" , , , , Jan Kara , "Matthew Wilcox (Oracle)" , "Mateusz Guzik" , "Gautham R. Shenoy" , Rasmus Villemoes , , , Swapnil Sapkal References: <20250306113924.20004-1-kprateek.nayak@amd.com> <20250306113924.20004-2-kprateek.nayak@amd.com> <20250306122807.GD19868@redhat.com> Content-Language: en-US From: K Prateek Nayak In-Reply-To: <20250306122807.GD19868@redhat.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SATLEXMB03.amd.com (10.181.40.144) To SATLEXMB04.amd.com (10.181.40.145) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PEPF0000000B:EE_|PH7PR12MB7939:EE_ X-MS-Office365-Filtering-Correlation-Id: a439caaf-e806-45ba-3964-08dd5cc34b0b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|7416014|376014|36860700013|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?T3JmWno0WUtUSk5lUlYzVnZYNlBEMUgzaHhva1pWVExTSzViTEdjdVFWZGxT?= =?utf-8?B?K1hRYWdaN3BsQ0NWWDdNVjRPU3lZTStoV2JSak5QUExrc3F3Z0N0MUNqdlFi?= =?utf-8?B?N1AxY05KS1dVbVFHbHZsendxZWJCUE8vNWdTa3IvMXdRM0tCd0JVOUxVT2RN?= =?utf-8?B?b0lrbFZIOXJjQ2xaV1pTTW4yQnZ5bXhJZzJCS1F0blc5cld3TWl3YTJpNngr?= =?utf-8?B?MFJIYXJheU9RNDJOc3dsbmcxd1RzMEVHd0dmQUxJdlFBVFIwdzNMT2EyeURR?= =?utf-8?B?cXRBbmNhVzRaWk12ekovMUNnS2ZzbkdDSWFqYzhFcFFYSUJ2MW9aV1dxZG1p?= =?utf-8?B?TVJ6VjlacVpVa1BFS2NTOW12WVVIVTE3WTU2YmdiWUV6YWZxU3dqblZXOGRQ?= =?utf-8?B?QTk4dlVFRFJjOW9DV2JKUUQ2QisySDZMK2xHYXQ3bmJTdUJWS1BpSVcybkcv?= =?utf-8?B?Ylh3VmZSc0NmYmZoNnJFZlNCblRYVXk0bGUxMy9NTFVqQzJiK3BsdTRXSUIv?= =?utf-8?B?Nk5ZeWY3YzgxSzdGVDBNeld4NXBQNWZ1VlQ5YW85T2pBNVplNUNseDVieC9w?= =?utf-8?B?WkVyQ0pYdklJNHBzdWZra0lDY0tHSGRmcEo4bzBzRUJBV0lpbzZ3QVlOcE5v?= =?utf-8?B?NFBaNzlDWTVMYy9EMHAveitLNVpEMFNqbSswaWV4ZXVnTC9QV2NkK1JRTWMv?= =?utf-8?B?blk5VGJOM0xCb0pKM0tDcUU1SFNCNHZtSW1hVHBnZXZIY2FxQS80OVVkWEFQ?= =?utf-8?B?WEhzOGZwK2RnLzgrKzJBZGhIOXM4MFpsemhHdG9wMUN0eHo1bGFidGFSb2l4?= =?utf-8?B?Mkt5b3BRdXZmUnRHRHZjSDZBcGMrL2R1RTZVRzMwUnlMQkZNMTQ4RHZhK0dq?= =?utf-8?B?ZFIwNUNtbXJjOGtQWHZnYTltYkZ4RGRreTNaUHN2TUZZR2xNb2kvbnVla1d3?= =?utf-8?B?SGNUZmJQZC9pbzZzMHF2eHlxMDlUWEF0MGo5T25xWHl0cERmUjFKNmowaGF5?= =?utf-8?B?TTZFanVIWTMwMU5rcWdjRTl6OXM2SzFzUFZ3enhOR1BkMVdVRGpQMEo3amx5?= =?utf-8?B?dWVGUjRrQ2F6VWg1ekhPMlk2QlRQTXlFcS9zL2NsOWZvbnNmemRJeFNDa0R6?= =?utf-8?B?NUgweUpTckw5RktObXVHa2FTUitVRFNacTlOT2dhRXZNUlkwU09lT0tLWm5Z?= =?utf-8?B?RFpDaVNzZGZGWXpmbGFMMHAzZmkzazdjWTJHK0JacnJPdHF1UDBnTlR0ZW5X?= =?utf-8?B?RVJMNXNnR0ZNUURWVXlQYmNjUHVKV2lGNms4VThtcFB4OHBEekFNWHQ1QjUx?= =?utf-8?B?ZE1Ic25NNlFkNXdKaG45d1RLQWZ6WVZsdGV5VUtoV3A3TkFvRFMySlFMaTJV?= =?utf-8?B?aGFRU2JIbWx0WUxtV0JMeHV6Qk0wMEZtZ2grNGxKQ2x4am1Gd3B0NHdDWDM0?= =?utf-8?B?aU1hdlM0V29KVmI2K3JFbC9MdDkrM0dxS2Ivc2dtdHZyVmZwNytVZkQ4TGZv?= =?utf-8?B?LzRoQ0VDNUJIWVFMUHZnRTY4WWM0NndObU8wcXhDbmIvTTBwRVgxVXhYSGVW?= =?utf-8?B?RmtLR1g1czJLZWh3TzhnWldEU0NYc2trMzhuL1gyUXRVbGxCMDl1TWxTNnpH?= =?utf-8?B?WE0wQTdxSXpLT21xVW9lM0RXOUdhOG5LanZ4UXVsQU9Kd1BvUzdjR0JJVnNy?= =?utf-8?B?TFFOckVBd2lZbFBuUlRJQkJIWWJ4Wkk1a0JjUktxREFrOFpkYXlmaGpxRDlT?= =?utf-8?B?YzhDN2lPWGRXcndnRGFUNFZ0V2NTbnhsMEd3QW1PODc0bEowM3N5eWRvaTZk?= =?utf-8?B?NzQ4YjgxTXFzT2VGZCtUR0I0eEhoY0dNYTQ0RnNxU2IzSnhiWGsxMXM4ZExQ?= =?utf-8?B?N3JMM0tGK05ra1B3SFIxcTZ5ak1ES2pHS2ZuMVUrektUWHI2V2NjaDBYTVd4?= =?utf-8?B?MUVrUytld2Z1TEVKUmdkLzRqK0xkVDloSHE3aDNsVFNpdHBRZkhNRGt0am1v?= =?utf-8?Q?i/6UisuRjZ4BVbItedHnKkv9S99f9w=3D?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:CAL;SFV:NSPM;H:SATLEXMB04.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(7416014)(376014)(36860700013)(1800799024);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Mar 2025 15:26:40.3258 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: a439caaf-e806-45ba-3964-08dd5cc34b0b X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[SATLEXMB04.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CH3PEPF0000000B.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH7PR12MB7939 Hello Oleg, On 3/6/2025 5:58 PM, Oleg Nesterov wrote: > On 03/06, K Prateek Nayak wrote: >> >> @@ -1272,6 +1272,10 @@ int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots) >> struct pipe_buffer *bufs; >> unsigned int head, tail, mask, n; >> >> + /* nr_slots larger than limits of pipe->{head,tail} */ >> + if (unlikely(nr_slots > BIT(BITS_PER_TYPE(pipe_index_t) - 1))) > > Hmm, perhaps > > if (nr_slots > (pipe_index_t)-1u) > > is more clear? Indeed it is. I didn't even know we could do that! Thank you for pointing it out. > > Oleg. > -- Thanks and Regards, Prateek