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([2001:a61:13de:8701:3ac2:500e:384:fbe1]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4908ecb5238sm13644335e9.24.2026.05.28.02.56.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 May 2026 02:56:56 -0700 (PDT) Message-ID: <5099d6cc-c8bc-4fdc-97cf-31e96a57e0c1@suse.com> Date: Thu, 28 May 2026 11:56:55 +0200 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] usb: misc: yurex: fix ordering of usb_deregister_dev() and usb_set_intfdata() To: Junzhe Li , gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260528082751.204898-1-ginger.jzllee@gmail.com> Content-Language: en-US From: Oliver Neukum In-Reply-To: <20260528082751.204898-1-ginger.jzllee@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 28.05.26 10:27, Junzhe Li wrote: > In yurex_disconnect(), usb_set_intfdata(interface, NULL) was called > before usb_deregister_dev(interface, &yurex_class). > This opens a race window with usb_open() in the USB core: > > T0 (yurex_disconnect) T1 (usb_open) > -------------------------- ------------------------- > usb_set_intfdata(iface, NULL) [t0] > fops = usb_minors[minor] [t1] > /* fops still valid here */ > usb_deregister_dev() > usb_minors[minor] = NULL [t2] > file->f_op->open(inode, file) > yurex_open() > dev = usb_get_intfdata() [t3] > /* dev is NULL! */ Yes, but yurex_open() checks for dev == NULL Could you please elaborate? Regards Oliver