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AJvYcCU/i9QptG+QNQ5gvxCgYDMLx7n6zN/gxcDq3V0h3t0+UPbuVP7/ulgvir72Xtzyn+J8DKIoUbh8vbVqFAc=@vger.kernel.org X-Gm-Message-State: AOJu0YwJ/NshGL2bNJDhew0ZSEjuZpx26Y2wB2wFOoUZecTmQ8Wz2IhX jgd025/F0lP5DnnhDlGDaBpOrFvf+nglOQsVX0L0bJSWdZEx4r3vjggM+vHRujhKHpkb8hiTjQN X5y7zZZNeHxHznMBUNknMC0F+jDUSb6rzUR76S+ww X-Gm-Gg: ASbGnct2shAxTXo7axbFxuwRFgcMRdfqmCPzVP4i57pIruU1Agl64uWtcc5UGaR6pwV G4IjVOuFbrcQ3ComEzYsDtNcg1jIwmrFbsagDdRIS/AgtXjx9wSnqzqw9PfWTfe0BAAXC1/TT81 3paJ9NVSNXmRLOpSDR7ZEwo4NIgM64S4OsLHkm0Xaq9cmL+KXpkGBB4stc2KVlK10GThbyByV8Y 8xvVI2bWHgE2i9AyJwSkSNPl7ym+UlXXOVypYn5B/wF/RY4j+A= X-Google-Smtp-Source: AGHT+IFsBJFrAVwoybcbClhbtkk6+q8fn0XpsL29CyxbYcZsn01RsMz0QJdas5oeFENVsTV7mWK0xrlHVrkZaylEWb4= X-Received: by 2002:a17:90b:3f0c:b0:311:e8cc:4248 with SMTP id 98e67ed59e1d1-31c9f44e087mr26700843a91.33.1752958069394; Sat, 19 Jul 2025 13:47:49 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <1752870014-28909-1-git-send-email-haiyangz@linux.microsoft.com> <20250718163723.4390bd7d@kernel.org> In-Reply-To: <20250718163723.4390bd7d@kernel.org> From: Kuniyuki Iwashima Date: Sat, 19 Jul 2025 13:47:37 -0700 X-Gm-Features: Ac12FXy6EAOOfaaxCqmoRw0ddlTwqZX2GFu92iR5XeK54Otp2RZbW_v44V-SJDg Message-ID: Subject: Re: [PATCH net] net: core: Fix the loop in default_device_exit_net() To: Jakub Kicinski Cc: Haiyang Zhang , linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, haiyangz@microsoft.com, kys@microsoft.com, wei.liu@kernel.org, edumazet@google.com, pabeni@redhat.com, horms@kernel.org, davem@davemloft.net, sdf@fomichev.me, ahmed.zaki@intel.com, aleksander.lobakin@intel.com, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Fri, Jul 18, 2025 at 4:37=E2=80=AFPM Jakub Kicinski wr= ote: > > On Fri, 18 Jul 2025 13:20:14 -0700 Haiyang Zhang wrote: > > The loop in default_device_exit_net() won't be able to properly detect = the > > head then stop, and will hit NULL pointer, when a driver, like hv_netvs= c, > > automatically moves the slave device together with the master device. > > > > To fix this, add a helper function to return the first migratable netde= v > > correctly, no matter one or two devices were removed from this net's li= st > > in the last iteration. > > FTR I think that what the driver is trying to do is way too hacky, and > it should be fixed instead. But I defer to Kuniyuki for the final word, > maybe this change is useful for other reasons.. I agree that it should be fixed on the driver side. I don't think of a good reason for the change.