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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4999d0788dasm41047085e9.4.2026.08.17.07.46.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Aug 2026 07:46:05 -0700 (PDT) Date: Mon, 17 Aug 2026 15:46:04 +0100 From: David Laight To: Linkai Gong Cc: Greg Kroah-Hartman , Michael Zimmermann , Peter Korsgaard , Christophe JAILLET , John Keeping , William Wu , Marco Crivellari , Ethan Tidmore , Kees Cook , Chris Wulff , David Sands , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] usb: gadget: f_hid: do not copy_from_user() under a spinlock Message-ID: <20260817154604.70427ed1@pumpkin> In-Reply-To: <20260817061141.82597-1-gonglinkai@kylinos.cn> References: <20260817061141.82597-1-gonglinkai@kylinos.cn> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 17 Aug 2026 14:11:41 +0800 Linkai Gong wrote: > f_hidg_get_report() already copied the report from userspace into a > new entry, then called copy_from_user() again under > get_report_spinlock. That can fault and sleep in atomic context. > > Update the existing entry with memcpy() from the copy already taken. > > Fixes: a139c98f760e ("USB: gadget: f_hid: Add GET_REPORT via userspace IOCTL") > Cc: stable@vger.kernel.org > Signed-off-by: Linkai Gong > --- > drivers/usb/gadget/function/f_hid.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c > index 3c6b43d06a6d..e4621e5a0b69 100644 > --- a/drivers/usb/gadget/function/f_hid.c > +++ b/drivers/usb/gadget/function/f_hid.c > @@ -667,14 +667,9 @@ static int f_hidg_get_report(struct file *file, struct usb_hidg_report __user *b > ptr = f_hidg_search_for_report(hidg, report_id); > > if (ptr) { > - /* Report already exists in list - update it */ > - if (copy_from_user(&ptr->report_data, buffer, > - sizeof(struct usb_hidg_report))) { > - spin_unlock_irqrestore(&hidg->get_report_spinlock, flags); > - ERROR(cdev, "copy_from_user error\n"); How about a patch to remove the ERROR() from the earlier copy_from_user() error path? David > - kfree(entry); > - return -EINVAL; > - } > + /* Report already exists; data was copied before taking the lock. */ > + memcpy(&ptr->report_data, &entry->report_data, > + sizeof(struct usb_hidg_report)); > kfree(entry); > } else { > /* Report does not exist in list - add it */