Hi,
I'm facing a NULL pointer dereference in omap_hsmmc_start_command() on
an AM33xx board running 3.11-rc1 (DMA enabled).
A quick debug session showed that DMA engine timing leads to a very
reproducable race condition. In omap_hsmmc_request(), we have:
host->mrq = req;
omap_hsmmc_prepare_data()
omap_hsmmc_start_dma_transfer()
tx->callback = omap_hsmmc_dma_callback;
[*]
omap_hsmmc_start_command()
if (cmd == host->mrq->stop) [<-- oops]
...
It turns out that omap_hsmmc_dma_callback() (which sets host->mrq =
NULL) is entered just after the DMA submission, and *before*
omap_hsmmc_start_command() is called, consequently leading to an Oops.
I can debug this in more depth, but maybe someone has an idea already?
Thanks,
Daniel
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