From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f43.google.com (mail-wr1-f43.google.com [209.85.221.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC41A29B789 for ; Fri, 27 Mar 2026 19:24:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774639462; cv=none; b=iAe6B/N9zsqz8HPhUxfWGx8zFemSUY4h07/O40g1cY15e6Y9BU6xVMpvl1Z7PngH1HRdw91+LgudALzsRHIBb9L9sQSFp+TtkWtaSpNZAKSc5eBjjrvXP6wTrBjkmyJvSg1BUa17J6rGHoueqG/r8elz9AZKaBidJSIEqxQdvJk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774639462; c=relaxed/simple; bh=rluKZ4GNgHw5m1UevyUUuL0azCAMdHmPw2X6TkYJiKY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=SEN/em8lOIJKvIwl78dNrYDYO+IlS7ls+4NKD9cb0A70dFmcNHiJWMRQI6mzfXNR5h3rHDpLDdYBxSzF2R4S84muEhbzwjZAaKa4AUrGZ81J3QtavoDjJnafA+FLXuSED+Za+duxaYofuTw0/GUvUmO8wMAgocDFdEomSWsxLwo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=cXwjAzVB; arc=none smtp.client-ip=209.85.221.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cXwjAzVB" Received: by mail-wr1-f43.google.com with SMTP id ffacd0b85a97d-43b871dd06eso1452605f8f.0 for ; Fri, 27 Mar 2026 12:24:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1774639458; x=1775244258; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=bFbXTjy4NMbpj8pvI5YlNDL7NdTaJ2uAwsFcgGj2Y3A=; b=cXwjAzVBBFnI1hzS9QareltxaMVVXhvIlDFlfX3Y/RbrRoXzr4wjMGf7SlHU4ONaCb euG4sIOnECMSeQaMlwbpZUHbho80OGD/DC3iz5FfShMsjPgXSjnucLffxuAA0KHFD8sM ojzpmmASL7+s2K9p+yhkse5RFT4PTA9IBqQImfuXUSK3vnlSwl5uQdNm1PAbHFxS7J6N jJI4HMkEySWUjEZYnWhDuSOiZHxKbw9/0dJO2hxcbg5gKteVoW+WHSmMr7N2Eoq2dEUq 79hgEeK6cYlPb6uFPGT2JGeI8SWBL6LYOPWnTbUxMBhdqTCcacazWsfjno7bSNRRKUFz /j5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774639458; x=1775244258; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=bFbXTjy4NMbpj8pvI5YlNDL7NdTaJ2uAwsFcgGj2Y3A=; b=WtsiucwYgFz8yyBXVyC2herMwDkNa3vcZ1XrzKa2V3lC0s5TJfqHT4yQSZ6FCyPY5j aA1VadVzUZpe+jzIA+ZLt+FlB4f9HaxRoSwG3JG6YWSwsGCs03ZkUQYMazJYm4QEuojZ ANVoN/wFm6Q3Zm7/73W9K1hhMIfX9dYRYIbmojoQD3MBC0xOTMjCA7nF18tJQITJSDam XH1XhFbQvy1hhZR05FKrXNQMwvtGnLjbDmSGLTwqRus1wVsnS+wr4aU0kMCWG3DFP20R xrIWGHJ/3EZ079fyI7HygtgKvqo0cXNSJjb/dtqMkVLMD67ETm+1rvsnEeFRs0sDNZzc 61FQ== X-Gm-Message-State: AOJu0YyzYiJ+l4CvT6bushfDq4Qrn/umVJ4JIOVN+KwbcYU6ctdVIrS7 NfQs1LtijzpnKo5ETFsnH7tEIBEhPx9TlOw7ilJknCCjevTHn6XiNeB+ X-Gm-Gg: ATEYQzx+uwA4o8K/cOpRQtiowpO0s5g9WgMG+hoh5ExaU9vcCEuyjR/Uwy/Rfe7uTYO ve0/zudGRKzsXzEzvHh/28KYb0PAe6UcG+HYtRixZ4UxRs6pqyW8xRJiTLIndpqxpJMr3p6ywsa 0wFILmG9OdAmKWmi1L1IN4ATXo5Aa6yFTjW9BgsZ7Okdc/19/VwdnkdRwmnR3m+MzynNQfTxj3Q vViy0oWtqAma26+nXHEA+VQQ71xhTqhQgvYhWd42hMMOpeavsxedpOBaMIR2R6pCmxMwm2AjcIp LmWiLQy/qhI7LEvdTgNWA1pYHIhZL+GSBYgtnk7I4neON3F72p5f27axt/ZZhfktz5s3+YRtofd 5cnjsapULWypvOqOmdxB5dDlv75sxu8c28GHAG5nml1FAs6aGFRRfz7ZzEHuKO/vYEhOgb15ZIx wkechu+Luqr/+aUt4OEt2oQ8BxQ247hTrUjevLdcpdKfO7w9g4fF7vIEjEhiSoMjUwZPQjPEg6R phYdm0VHuEVRvA= X-Received: by 2002:a05:6000:3105:b0:439:c799:dbfa with SMTP id ffacd0b85a97d-43b9e9d97d5mr5819506f8f.9.1774639458215; Fri, 27 Mar 2026 12:24:18 -0700 (PDT) Received: from toolbox ([2a00:1e:8743:9700:a5c1:58f4:f0a9:10cd]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43cf2463dc2sm171956f8f.23.2026.03.27.12.24.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Mar 2026 12:24:17 -0700 (PDT) From: Michael Zimmermann To: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Michael Zimmermann Subject: [PATCH] usb: gadget: f_hid: don't call cdev_init while cdev in use Date: Fri, 27 Mar 2026 20:22:09 +0100 Message-ID: <20260327192209.59945-1-sigmaepsilon92@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When calling unbind, then bind again, cdev_init reinitialized the cdev, even though there may still be references to it. That's the case when the /dev/hidg* device is still opened. This obviously unsafe behavior like oopes. This fixes this by using cdev_alloc to put the cdev on the heap. That way, we can simply allocate a new one in hidg_bind. Closes: https://lore.kernel.org/linux-usb/CAN9vWDKZn0Ts5JyV2_xcAmbnBEi0znMLg_USMFrShRryXrgWGQ@mail.gmail.com/T/#m2cb0dba3633b67b2a679c98499508267d1508881 Signed-off-by: Michael Zimmermann --- drivers/usb/gadget/function/f_hid.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c index 8812ebf33d14..66be2e1282c1 100644 --- a/drivers/usb/gadget/function/f_hid.c +++ b/drivers/usb/gadget/function/f_hid.c @@ -106,7 +106,7 @@ struct f_hidg { struct list_head report_list; struct device dev; - struct cdev cdev; + struct cdev *cdev; struct usb_function func; struct usb_ep *in_ep; @@ -749,8 +749,9 @@ static int f_hidg_release(struct inode *inode, struct file *fd) static int f_hidg_open(struct inode *inode, struct file *fd) { + struct kobject *parent = inode->i_cdev->kobj.parent; struct f_hidg *hidg = - container_of(inode->i_cdev, struct f_hidg, cdev); + container_of(parent, struct f_hidg, dev.kobj); fd->private_data = hidg; @@ -1285,8 +1286,12 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f) } /* create char device */ - cdev_init(&hidg->cdev, &f_hidg_fops); - status = cdev_device_add(&hidg->cdev, &hidg->dev); + hidg->cdev = cdev_alloc(); + if (!hidg->cdev) + goto fail_free_all; + hidg->cdev->ops = &f_hidg_fops; + + status = cdev_device_add(hidg->cdev, &hidg->dev); if (status) goto fail_free_all; @@ -1588,7 +1593,7 @@ static void hidg_unbind(struct usb_configuration *c, struct usb_function *f) { struct f_hidg *hidg = func_to_hidg(f); - cdev_device_del(&hidg->cdev, &hidg->dev); + cdev_device_del(hidg->cdev, &hidg->dev); destroy_workqueue(hidg->workqueue); usb_free_all_descriptors(f); } -- 2.53.0