Re: [PATCH] bus: mhi: ep: Update read pointer only after buffer is written

[Jeff Hugo]

On 4/9/2025 4:47 AM, Sumit Kumar wrote:
> Inside mhi_ep_ring_add_element, the read pointer (rd_offset) is updated
> before the buffer is written, potentially causing race conditions where
> the host sees an updated read pointer before the buffer is actually
> written. Updating rd_offset prematurely can lead to the host accessing
> an uninitialized or incomplete element, resulting in data corruption.
>
> Invoke the buffer write before updating rd_offset to ensure the element
> is fully written before signaling its availability.
>
> Fixes: bbdcba57a1a2 ("bus: mhi: ep: Add support for ring management")
> cc: stable@xxxxxxxxxxxxxxx
> Co-developed-by: Youssef Samir <quic_yabdulra@xxxxxxxxxxx>
> Signed-off-by: Youssef Samir <quic_yabdulra@xxxxxxxxxxx>
> Signed-off-by: Sumit Kumar <quic_sumk@xxxxxxxxxxx>

Reviewed-by: Jeff Hugo <jeff.hugo@xxxxxxxxxxxxxxxx>