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([2a02:8084:e84:2480:228:f8ff:fe6f:83a8]) by smtp.gmail.com with ESMTPSA id k12sm17030398pfk.219.2020.06.16.06.47.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Jun 2020 06:47:50 -0700 (PDT) Subject: Re: [PATCH 2/6] arm64/vdso: Zap vvar pages when switching to a time namespace To: Mark Rutland , Andrei Vagin References: <20200616075545.312684-1-avagin@gmail.com> <20200616075545.312684-3-avagin@gmail.com> <20200616112418.GC11780@C02TD0UTHF1T.local> From: Dmitry Safonov Message-ID: Date: Tue, 16 Jun 2020 14:47:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200616112418.GC11780@C02TD0UTHF1T.local> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200616_064752_862497_040C32CA X-CRM114-Status: GOOD ( 11.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Catalin Marinas , linux-kernel@vger.kernel.org, Thomas Gleixner , Vincenzo Frascino , Will Deacon , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Mark, On 6/16/20 12:24 PM, Mark Rutland wrote: > On Tue, Jun 16, 2020 at 12:55:41AM -0700, Andrei Vagin wrote: [..] >> Whenever a task changes its namespace, the VVAR >> page tables are cleared and then they will be re-faulted with a >> corresponding layout. > > How does this work for multi-threaded applications? Are there any > concerns w.r.t. atomicity of the change? Multi-threaded applications can't setns() for time namespace, timens_install(): : if (!current_is_single_threaded()) : return -EUSERS; Thanks, Dmitry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel