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[130.126.255.72]) by smtp.gmail.com with ESMTPSA id g17-20020a05620a109100b00789e90a851asm4084589qkk.56.2024.03.19.15.49.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 19 Mar 2024 15:49:20 -0700 (PDT) Message-ID: <5fde8ace-a0ac-4870-a7fe-ec2a24697112@gmail.com> Date: Tue, 19 Mar 2024 17:49:19 -0500 Precedence: bulk X-Mailing-List: lvs-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: horms@verge.net.au, ja@ssi.bg, davem@davemloft.net, dsahern@kernel.org, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com From: Zijie Zhao Subject: [net] Question about ipvs->sysctl_sync_threshold and READ_ONCE Cc: netdev@vger.kernel.org, lvs-devel@vger.kernel.org, chenyuan0y@gmail.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Dear IPVS maintainers, We encountered an unusual usage of sysctl parameter while analyzing kernel source code. In include/net/ip_vs.h, line 1062 - 1070: ``` static inline int sysctl_sync_threshold(struct netns_ipvs *ipvs) { return ipvs->sysctl_sync_threshold[0]; } static inline int sysctl_sync_period(struct netns_ipvs *ipvs) { return READ_ONCE(ipvs->sysctl_sync_threshold[1]); } ``` Here, sysctl_sync_threshold[1] is accessed behind `READ_ONCE`, but sysctl_sync_threshold[0] is not. Should sysctl_sync_threshold[0] also be guarded by `READ_ONCE`? Please kindly let us know if we missed any key information and this is actually intended. We appreciate your information and time! Thanks! Links to the code: https://elixir.bootlin.com/linux/v6.8.1/source/include/net/ip_vs.h#L1064 https://elixir.bootlin.com/linux/v6.8.1/source/include/net/ip_vs.h#L1069 Best, Zijie