Re: [PATCH v2 1/1] net: fec: handle page_pool_dev_alloc_pages error

[Jacob Keller]

On 1/13/2025 7:48 AM, Kevin Groeneveld wrote:
> The fec_enet_update_cbd function calls page_pool_dev_alloc_pages but did
> not handle the case when it returned NULL. There was a WARN_ON(!new_page)
> but it would still proceed to use the NULL pointer and then crash.
> 
> This case does seem somewhat rare but when the system is under memory
> pressure it can happen. One case where I can duplicate this with some
> frequency is when writing over a smbd share to a SATA HDD attached to an
> imx6q.
> 
> Setting /proc/sys/vm/min_free_kbytes to higher values also seems to solve
> the problem for my test case. But it still seems wrong that the fec driver
> ignores the memory allocation error and can crash.
> 
> This commit handles the allocation error by dropping the current packet.
> 
> Fixes: 95698ff6177b5 ("net: fec: using page pool to manage RX buffers")
> Signed-off-by: Kevin Groeneveld <kgroeneveld@xxxxxxxxxxxx>
> ---

Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>