Re: [PATCH v2] drivers: net: xgene: fix: Out of order descriptor bytes read

From: David Miller
Date: Fri Jan 30 2015 - 21:25:15 EST


From: Iyappan Subramanian <isubramanian@xxxxxxx>
Date: Thu, 29 Jan 2015 14:38:23 -0800

> This patch fixes the following kernel crash,
...
> Software writes poison data into the descriptor bytes[15:8] and upon
> receiving the interrupt, if those bytes are overwritten by the hardware with
> the valid data, software also reads bytes[7:0] and executes receive/tx
> completion logic.
>
> If the CPU executes the above two reads in out of order fashion, then the
> bytes[7:0] will have older data and causing the kernel panic. We have to
> force the order of the reads and thus this patch introduces read memory
> barrier between these reads.
>
> Signed-off-by: Iyappan Subramanian <isubramanian@xxxxxxx>
> Signed-off-by: Keyur Chudgar <kchudgar@xxxxxxx>

Applied, thanks.
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