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McKenney" , Boqun Feng , Paolo Bonzini , Sean Christopherson , Wei Liu , Dexuan Cui , x86@kernel.org, Arnd Bergmann , Heiko Carstens , Christian Borntraeger , Sven Schnelle , Huacai Chen , Paul Walmsley , Palmer Dabbelt References: <20250823161326.635281786@linutronix.de> <20250823161653.580926530@linutronix.de> From: Mathieu Desnoyers Content-Language: en-US In-Reply-To: <20250823161653.580926530@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: YQXPR0101CA0060.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:c00:14::37) To YT2PR01MB9175.CANPRD01.PROD.OUTLOOK.COM (2603:10b6:b01:be::5) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: YT2PR01MB9175:EE_|YT2PR01MB11272:EE_ X-MS-Office365-Filtering-Correlation-Id: ef92d9d4-9597-4c54-fd7d-08dde3ee4d65 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|366016|1800799024|7053199007; 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> - u64 rseq_cs; > > if (flags & RSEQ_FLAG_UNREGISTER) { > if (flags & ~RSEQ_FLAG_UNREGISTER) > @@ -557,11 +555,9 @@ SYSCALL_DEFINE4(rseq, struct rseq __user > * avoid a potential segfault on return to user-space. The proper thing > * to do would have been to fail the registration but this would break > * older libcs that reuse the rseq area for new threads without > - * clearing the fields. > + * clearing the fields. Don't bother reading it, just reset it. > */ > - if (rseq_get_rseq_cs_ptr_val(rseq, &rseq_cs)) > - return -EFAULT; > - if (rseq_cs && clear_rseq_cs(rseq)) > + if (put_user_masked_u64(0UL, &rseq->rseq_cs)) > return -EFAULT; > > #ifdef CONFIG_DEBUG_RSEQ > -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com