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Commit 8ac60ffb authored by Kees Cook's avatar Kees Cook Committed by David S. Miller
Browse files

net: stmmac: Avoid VLA usage 

In the quest to remove all stack VLAs from the kernel[1], this switches
the "status" stack buffer to use the existing small (8) upper bound on
how many queues can be checked for DMA, and adds a sanity-check just to
make sure it doesn't operate under pathological conditions.

[1] http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com



Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarJose Abreu <joabreu@synopsys.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 795d8098

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+5 −1
Original line number Diff line number Diff line
@@ -2022,7 +2022,11 @@ static void stmmac_dma_interrupt(struct stmmac_priv *priv) 
				tx_channel_count : rx_channel_count;

	u32 chan;

	bool poll_scheduled = false;

	int status[channels_to_check];

	int status[max_t(u32, MTL_MAX_TX_QUEUES, MTL_MAX_RX_QUEUES)];



	/* Make sure we never check beyond our status buffer. */

	if (WARN_ON_ONCE(channels_to_check > ARRAY_SIZE(status)))

		channels_to_check = ARRAY_SIZE(status);



	/* Each DMA channel can be used for rx and tx simultaneously, yet

	 * napi_struct is embedded in struct stmmac_rx_queue rather than in a