From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f53.google.com (mail-pj1-f53.google.com [209.85.216.53]) (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 4B4F83DB64A for ; Tue, 25 Aug 2026 11:07:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787656045; cv=none; b=LsOAXOqPVwDGiUUAlFyAyS4SDM1T64wqFg8ZY8qdUFz46LT5p8CwYGObhhuzgriQEIwNVf9Q2xCgati6HrSoipHKrBjvNS2FwpeEHpt0nWkT+tGAHzzv/eVy3GU1vwOUNHd9oT8P9MQdpTaBP5y7CW4oB3LtdlGe0P8obOENepI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787656045; c=relaxed/simple; bh=FbsJrNLWRnA5FZelNcQumZAVr9SQGildHFWErfp7iE4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fMQLX/9319Jy7k6Jv8fgHY9S283yyUAjYTD2Bl//fYnW1nvvCZWlsIF9vpYoapu2SLoOBkAqjCaATnYgMkcW0i5p8NS8cT4QjYxeTbXgZNn7FwoXHSfxlIBFSdkb6p44JffpGWX9u0mdNfD1/VYJ0nDQQU7emAFyAtvyCmqNAQY= 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=Uq6ZO6My; arc=none smtp.client-ip=209.85.216.53 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="Uq6ZO6My" Received: by mail-pj1-f53.google.com with SMTP id 98e67ed59e1d1-38e7109321dso3336011a91.3 for ; Tue, 25 Aug 2026 04:07:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1787656043; x=1788260843; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=ygSmQPvZ/Nd116NGGtGNonu+zeK52756mGmLYMo4WT0=; b=Uq6ZO6My62FnBKE7nPkf5mwsA9naTz0tJPh9eaoazG5ZLko1o/HI/H6LzTDaHWpY0M heou2eemSfYbu5qUMgCWZsrXBZg5eUjkhnC6bVCg3H8TfDNcPX6gN8a0PgvkKIBpweWx 0pShRP8GfFtFF9kPhowYheCgRJ1/DNR6T1pFvkURafpAeiQgIaa5VuuO7mAduZLbSxRY 7HmMbTK84EB4z+w1xOGmAlyRrehCVqqMJyue0d/CljLGVNNJ+SrQe7Bg4TVIUr6qrTtm /WmJimHNGfblbd+2ZBndzXCGM3GQCV2TVs5nsKT0/mKtbMf9OmIkCnyiOaPSDlUQrUEn LBUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787656043; x=1788260843; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=ygSmQPvZ/Nd116NGGtGNonu+zeK52756mGmLYMo4WT0=; b=ssRAnTq+KR+6khvYu8jqY9G1yOExYMAoecQfAo/h+WW54GF7PQocsZu8dtn+1gfB2t 9Yto0qdv0FinjcZtXpATlU/IBAD0BHJFlRaNfahvrkl3poQFwTyl2AyCVR0S3geukRrx V9I1nDC8EXn7rQ83R5rPHxIB+e+/4ijVvQNKxPSv4KZuud3K+jXEbpq3XQp5Q7lWcgxx OzvoHmFloeVll+Ecs7srzA0U2EMi9JW3vlo3U6Qru92uiX5pqpwdBtdKIFOfANok/l0A SBeqDY2+H6V7mQ1BNDsGdaN/1JuqP9TBOyKIUzdyUavUVZXQdbRLU1HpJupYYyHstO6v 84VQ== X-Forwarded-Encrypted: i=1; AHgh+Rr7pqbo/orA9+VXdn41J1Jp+gf1KWrF/rkmb0q2FM1edxsW/54mOvFCvbzDbh2sx5OseYTdugo=@vger.kernel.org X-Gm-Message-State: AFuF++mWseQ/Q7XyhQo8JoXGx+ATiAru47tA1fWl5VSPNOf8Lvi1jHYc n8Pwf8EQY8jENHKAe9uB1oxzf3Ji5a8JBbt5BJTUqWQII4nVgWvUB5kd X-Gm-Gg: AR+sD1238413ojWcerOcFKJ/TmmXP6gU0cNe0uZ8p3zJXHfoZ0ftDgs46ve1dgDASuI bdlokIz7TPVzBjgHhYZGyI+MgqEFNL56ACAa4dod9pmGLkfjOXAnED6IorjnYHQIamTMYn1Gjjb az76p1mcnJ5xJ3Nhqt5orHdFPdq6S40XK8gj+gast9dFMH8OpZMt1nqM+mXECzDYm3+qsg/nOg8 jZmkphT+NNkljr96/NxzDtyRLyJ6ULSBNh1Sq++Ce22FjMwjNI8QfdAFHfDsaV+Ymd3VcByiUtC tEEazKbdPlZuukWokIPz+sPo1ehEiBPUQvUxebna2nfcLytx310D25Cwuk5fwkPD37Ojltfgg9C nCHLC28WeV8BUGZnvHSOiQ2kvgV2k+Pb5zOj4EuOf6GmB75R9yf3shfI+JA3FfPBHmzrkcf+jdB mFhWlJT4D2dxD79GhBxwQjg4esca+XPLIAK+FfUzFdEbwOKtJKyWz265nGY7CfFVyLTX55wNdbW QcoXIo7o9NogJYYtemaEM45PdlUOqArGiacouDuQYNx X-Received: by 2002:a17:90b:2685:b0:380:21b7:e727 with SMTP id 98e67ed59e1d1-396465587c5mr11510630a91.14.1787656042512; Tue, 25 Aug 2026 04:07:22 -0700 (PDT) Received: from localhost ([2409:40c4:101c:e5a9:a28f:e499:1b07:43b3]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-327f91d36f9sm54570232eec.16.2026.08.25.04.07.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Aug 2026 04:07:21 -0700 (PDT) Date: Tue, 25 Aug 2026 16:37:15 +0530 From: Lovekesh Solanki To: jjy600901@snu.ac.kr Cc: brauner@kernel.org, eulgyukim@snu.ac.kr, gregkh@linuxfoundation.org, jack@suse.cz, kees@kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, mjguzik@gmail.com, stern@rowland.harvard.edu, viro@zeniv.linux.org.uk, stable@vger.kernel.org Subject: Re: [PATCH] USB: gadget: fix NULL pointer dereference in gadget_dev_ioctl() Message-ID: References: <20260824113510.1141236-1-jjy600901@snu.ac.kr> <20260825105801.319997-1-lovekeshsolanki00@gmail.com> Precedence: bulk X-Mailing-List: stable@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: <20260825105801.319997-1-lovekeshsolanki00@gmail.com> On Tue, Aug 25, 2026 at 04:28:01PM +0530, Lovekesh Solanki wrote: > gadget_dev_ioctl() reads dev->gadget outside the dev->lock, while > gadgetfs_bind() writes it without holding the lock. A concurrent > bind can update dev->gadget and dev->state under the lock while the > ioctl thread holds a stale NULL copy, causing a NULL pointer > dereference at offset 0x28 (gadget->ops->ioctl). > > Read dev->gadget inside the locked region, before the state check, > so the state and gadget pointer are always consistent. > > Cc: stable@vger.kernel.org > Reported-by: Eulgyu Kim > Link: https://lore.kernel.org/all/20260824160022.2378192-1-jjy600901@snu.ac.kr/ > Reported-by: Jaeyoung Chung > Link: https://lore.kernel.org/all/20260824160022.2378192-1-jjy600901@snu.ac.kr/ > Signed-off-by: Lovekesh Solanki > --- > drivers/usb/gadget/legacy/inode.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c > index d87a8ab51510..e9f7d7c1a6a3 100644 > --- a/drivers/usb/gadget/legacy/inode.c > +++ b/drivers/usb/gadget/legacy/inode.c > @@ -1251,14 +1251,15 @@ ep0_poll (struct file *fd, poll_table *wait) > static long gadget_dev_ioctl (struct file *fd, unsigned code, unsigned long value) > { > struct dev_data *dev = fd->private_data; > - struct usb_gadget *gadget = dev->gadget; > + struct usb_gadget *gadget; > long ret = -ENOTTY; > > spin_lock_irq(&dev->lock); > + gadget = dev->gadget; > if (dev->state == STATE_DEV_OPENED || > dev->state == STATE_DEV_UNBOUND) { > /* Not bound to a UDC */ > - } else if (gadget->ops->ioctl) { > + } else if (gadget && gadget->ops->ioctl) { > ++dev->udc_usage; > spin_unlock_irq(&dev->lock); > > -- > 2.55.0 Apologies, the Link tag is wrong, correct one is https://lore.kernel.org/all/20260824113510.1141236-1-jjy600901@snu.ac.kr/ Should I send a v2 with fixed tag? Regards, Lovekesh