On 10.06.2022 17:33:37, Rhett Aultman wrote:
> The gs_usb driver allocates DMA memory with usb_alloc_coherent() in
> gs_can_open() and then keeps this memory in an URB, with the expectation
> that the memory will be freed when the URB is killed in gs_can_close().
> Memory allocated with usb_alloc_coherent() cannot be freed in this way
> and must be freed using usb_free_coherent() instead.  This means that
> repeated cycles of calling gs_can_open() and gs_can_close() will lead to
> a memory leak.
> 
> Historically, drivers have handled this by keeping an array of pointers
> to their DMA rx buffers and explicitly freeing them.  For an example of
> this technique used in the esd_usb2 driver, see here:
> https://www.spinics.net/lists/linux-can/msg08203.html

Better reference the commit or use a link to lore.kernel.org:

928150fad41b ("can: esd_usb2: fix memory leak")
https://lore.kernel.org/all/b31b096926dcb35998ad0271aac4b51770ca7cc8.1627404470.git.paskripkin@gmail.com/

Marc

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