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([2a02:3033:28e:551d:9975:219f:1622:8b8d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49ce58da3acsm802674335e9.0.2026.09.07.01.17.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Sep 2026 01:17:42 -0700 (PDT) Message-ID: Date: Mon, 7 Sep 2026 10:17:38 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] USB: cdc-acm: fix racy TIOCMIWAIT implementation To: Johan Hovold , Oliver Neukum , Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260907065501.101013-1-johan@kernel.org> Content-Language: en-US From: Oliver Neukum In-Reply-To: <20260907065501.101013-1-johan@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 07.09.26 08:55, Johan Hovold wrote: > The wakeup condition needs to be checked after adding the task to the > waitqueue and updating the task state to avoid missing a racing modem > status update or disconnect. I am sorry, but in this case I have to ask: Isn't TIOCMIWAIT inherently racy against the hardware? Regards Oliver