Re: [PATCH] usb: gadget: f_hid: avoid copy_from_user() under get_report_spinlock

[sashiko-bot@kernel.org]

> f_hidg_get_report() copies the userspace report into a freshly allocated
> 'entry' before taking get_report_spinlock.  When the report id is already
> present in the list it then copies the same userspace buffer a second
> time into the existing entry, this time while holding get_report_spinlock
> (acquired with spin_lock_irqsave()):
> 
> 	spin_lock_irqsave(&hidg->get_report_spinlock, flags);
> 	ptr = f_hidg_search_for_report(hidg, report_id);
> 	if (ptr) {
> 		if (copy_from_user(&ptr->report_data, buffer,
> 				sizeof(struct usb_hidg_report))) {
> 
> copy_from_user() may fault and sleep, which is not allowed while holding
> a spinlock with interrupts disabled:
> 
> [ ... ]
> also drops a redundant second read of the user buffer.
> 
> Fixes: a139c98f760e ("USB: gadget: f_hid: Add GET_REPORT via userspace IOCTL")
> Cc: stable@vger.kernel.org
> Signed-off-by: Yu Zhang <yuz08559@gmail.com>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261020051446.92179-1-yuz08559@gmail.com?part=1