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Thu, 22 May 2025 05:32:17 -0700 (PDT) Received: from hoboy.vegasvil.org ([2600:1700:2430:6f6f:e2d5:5eff:fea5:802f]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-742a96de0fbsm11479196b3a.18.2025.05.22.05.32.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 May 2025 05:32:17 -0700 (PDT) Date: Thu, 22 May 2025 05:32:15 -0700 From: Richard Cochran To: Jeongjun Park Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, yangbo.lu@nxp.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] ptp: remove ptp->n_vclocks check logic in ptp_vclock_in_use() Message-ID: References: <20250520160717.7350-1-aha310510@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250520160717.7350-1-aha310510@gmail.com> On Wed, May 21, 2025 at 01:07:17AM +0900, Jeongjun Park wrote: > There is no disagreement that we should check both ptp->is_virtual_clock > and ptp->n_vclocks to check if the ptp virtual clock is in use. > > However, when we acquire ptp->n_vclocks_mux to read ptp->n_vclocks in > ptp_vclock_in_use(), we observe a recursive lock in the call trace > starting from n_vclocks_store(). > The best way to solve this is to remove the logic that checks > ptp->n_vclocks in ptp_vclock_in_use(). Acked-by: Richard Cochran