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@xxxxxxxxx/ Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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