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[2a02:3100:610f:ecfc:4dfb:2ac9:70ba:48bd]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4887a34a570sm1809789f8f.13.2026.09.24.14.22.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Sep 2026 14:22:25 -0700 (PDT) Message-ID: <798e192b-b10f-46ee-8059-bf8d6db058b9@gmail.com> Date: Thu, 24 Sep 2026 23:22:24 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/4] net: hsr: shrink seqnr_lock to sequence counter updates To: Sebastian Andrzej Siewior Cc: netdev@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, andrew+netdev@lunn.ch, shuah@kernel.org, kees@kernel.org, petr.wozniak@gmail.com, qingfang.deng@linux.dev, fmaurer@redhat.com, luka.gejak@linux.dev, xiaoliang.yang_1@nxp.com, skhawaja@google.com, liuhangbin@gmail.com, stable@vger.kernel.org, sdf.kernel@gmail.com, syzbot+fbf74291c3b7e753b481@syzkaller.appspotmail.com References: <20260809121455.1745-1-xiexinet@gmail.com> <20260809121455.1745-3-xiexinet@gmail.com> <20260923103725.kB_5-sDD@linutronix.de> Content-Language: en-GB From: Xin Xie Autocrypt: addr=xiexinet@gmail.com; keydata= xsDNBGpiHugBDADJ5KuJaOYfUx7TGbRw0UE1km4dLnJomCSNtgq2T9BqgZ6TRPEy37soAmW3 XxCPvhfL6CPLldzy6O6EkUD7/8zlbQP1DM6gUIQUyKxxkb8uR+oCogDKjsxt0QPycP/dR9fk SL4qKReprnkOOcGeLahLHzofVdn46mc5igCBsAA/PPSpo1GqsfGk+zYV97rSVa8zhnSXsqZ/ 9DbUfQynZKVqYN4tm1B30JE5SEWDCko95Qw9fAORX2W356MOQJGr05z9qMSy7CkF7bAUkziG d6ZSPsGEsel5jYByP8ZvwQ2A8kdKpRy8+zQCaC+vEotTH7Fs7SIzE/Z5mEVIi1xQqEzN1rqG BW7KgzRDWjw8lKsoBbxv20nfhUzuZLan2HzUJ+LxZ18Os4zkWg9sxHgMi+AGqn/+0ppbDcOH 9Jm072/xA7O1MCXLgr4FOP+4PJH1vcqU+0EZVz7KCjrwkdz+l5Ojso2FLXq2MGoqWGShIsDV bF1JYpgm4spdPbnISkidUC0AEQEAAc0cWGluIFhpZSA8eGlleGluZXRAZ21haWwuY29tPsLB DQQTAQgANxYhBAHOahKZFnMu2n/CxrTrSufyPi3LBQJqYh7oBQkFo5qAAhsDBAsJCAcFFQgJ CgsFFgIDAQAACgkQtOtK5/I+LctmngwAlmrGPWnWxDW6PSJeR9SM0faqwuY33TWAE35nshm/ EEkBgpVVhG4z4Cdy7L+6TG6NHVDnvl+IHLyyOZlL3LQPQIpiKVgo6jHmm9TF6mK+Vo3nsXAA uSJYu9iY9Aywmy2JVQ15ttQ0NfcoZ0sV14bT7pSr9zXB6D8p3XA4AQI6IBeLvj993Z1+tPyC 6BJ+2aWWLBx7xGpFo3X8dhjS/Lm8QoietKbI+ACefKKCDNiM2KG53P76wdXJp52u4dqP6eFc +Qv35QefnALoPkOGQEdd1qvUycyZhuaCj8h0AxDu7bL3G/IM8G2K8qsbSJuui8zCSZ9b/QZf H7u1nevPOgxyWC1Pep/TbRZ62ktn8lrmWA8PZjuaJJQGjahuK1GgTQZNG+7DB7NwjLr6aXIm JirtT4FeR+IUovvL/ll+VHzpGpFbgXz4GTsWsikQkT1huFSB8MRLlWMXdAKblL96L754j8Z5 p/YV26YTppXI56uJ3XyOwZSrfrK1pfqNIp2Yr9vUzsDNBGpiHukBDACePM1YZ1FvAiFay/2v KVDNpuazmpVb1CBFy+rqM9HcuHe+5CuxLd4RI4hb0qmjlm5Vi5M8+AuNB/wi/f8oDuhJwlMn v9L0lfgpRRdShnB26hnt2wWwWFgOU3BwymSruxhEYq+eIjjxCAo6yW7Qm+ArZ+riETMI67sy ZyLx6o4yRiWxOrh1nhwV/f6PIOl+Iv4yLAG3eFXpU7/EZpim610bKMwcXEpiRkf3NjiflIha adoKHV0LCiVNrU7r8TICjjnugpl1tXAR2RlaRcSxmvOzrXY2O/xBLpwPr5erbdk8RCaxUzS0 kK0hw+/On3Sr4Z4gtLl2xtDkjRh3KQ9ZqMPrFD/5XOs842ueNivwIyAf2kQJjKfJGWc771EM 0ZWo1r1AthbuM+IeN5QM74rMJxaf5WyDX3ZeqBA55fCJGJ3zrp7Tqeoq8DYufiNkppE9S71z Cvxva2f8mUWTlTUf8s33sRD7C87XpT0whKpn1I9/nJB9Kb0dKyRCdcsT4o1ynxUAEQEAAcLA /AQYAQgAJhYhBAHOahKZFnMu2n/CxrTrSufyPi3LBQJqYh7pBQkFo5qAAhsMAAoJELTrSufy Pi3L/iwL/3aoCeq19Pog3fqisRyEZeX8pXw2GYlrJWYoM0mQ1USaTpdsMwCXaoFMoSBqid0F VPrqlH4bSIEEAzVmFPX0NjGhREDMrQ9eR5S9yqSpBvX+hz+xgpt4NOPhbVQmV+9f4lX9TJT7 GOO3EX2eeokg6ZAISycCAx7srXuc8oyRTJtnUQziH9GXrEeon88LHf1QHg0Z0sL/c7DfDqvW 9924M4ngQAZ8RgCBGZocoWuXCemSPkfQVLt5DzycSgSQODhbNSEmr+jb1V9Svf9D9k0CQfEY cB3uwOHWb6Z/yaEARbGZPSPn89YjXBncQTpgSvUM578b5x3pKi6PjZB/hwtUsRgrWGWoIwRi +ZmcHnCzsuo6uuNYX8VvmWqYsVajykjnpjdCGmU89QUsVmrtnDPBrfr8VVJcZPnCJhE595Pk LO29Oj0au9kr7kMW5Q+fBeHj5zz6VggAaRRU74/sgtwLODBWESPZ9LqUUdB5L/XbrSq2VDlD sNySbH3veZ/55EtlXA== In-Reply-To: <20260923103725.kB_5-sDD@linutronix.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 23/09/2026 12:37, Sebastian Andrzej Siewior wrote: > This fix relies on the bitmap seq nr handling while the Fixes commits > below do not have it. Doesn't this revert the synchronisation change > leading to the problem it tried to solve at least in the stable kernels? You're right. Shrinking the lock can reintroduce ordering drops on pre-bitmap kernels, and the sender's bitmap does not make reordering safe for older peers. Across ten VM runs per mode against an unmodified pre-bitmap HSRv0 peer, the narrowed-lock control delivered 19,128 of 20,000 test frames at the peer's master. The ordered-consumer prototype delivered all 20,000 exactly once. I'll rework patch 2 around a single consumer for locally numbered traffic, including supervision. Each frame would be submitted to all its lower devices before the next frame is numbered. An idle caller would process only its own input inline; contention or re-entry would queue input to one BH worker. No HSR lock would be held across segmentation or dev_queue_xmit(). Deferred inputs would retain their core TX recursion depth. This preserves the original per-lower submission ordering without relying on bitmap tolerance. On PREEMPT_RT, consumer ownership would not provide priority inheritance from queued producers; progress depends on the consumer being scheduled. I will test this explicitly. -- Xin