Messages in this thread | | | Date | Mon, 8 Feb 2016 16:15:42 +0000 | From | Mark Brown <> | Subject | Re: [PATCH] spi: Fix incomplete handling of SPI_MASTER_MUST_RX/_MUST_TX |
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On Fri, Feb 05, 2016 at 10:30:24AM +0530, Purna Chandra Mandal wrote:
Please fix your mail client to word wrap within paragraphs at something substantially less than 80 columns. Doing this makes your messages much easier to read and reply to.
> Idea is good, but not sufficient. > Dummy buffers are _reallocated_ to accommodate larger size of transfer. In this if > [originally NULL] .rx_buf/.tx_buf is not reset back to NULL after the transfer > is over spi-core will find those .rx/tx_buf non-NULL in next _transfer() call and > will pass the stale rx/tx_buf to spi controller driver which will definitely > corrupt the memory and crash the system.
This needs to be clear to readers; a fairly obvious way of dealing with this would be to rellocate down to a page rather than freeing.
> Above all the whole design depends on trust that core will not play with any data-structure > which will break object-oriented/layered approach. So better to undo the modification > (when needed to facilitate some functionality) unless core wants those information to be passed > back to caller/client for reporting success or error or else.
That's really not the case, we already make a range of other modifications to complete partially filled transfers in order to simplify driver code. [unhandled content-type:application/pgp-signature] | |