On 15-01-19, 17:15, Leonid Iziumtsev wrote:
> Once the "ld_queue" list is not empty, next descriptor will migrate
> into "ld_active" list. The "desc" variable will be overwritten
> during that transition. And later the dmaengine_desc_get_callback_invoke()
> will use it as an argument. As result we invoke wrong callback.
>
> That behaviour was in place since:
> commit fcaaba6c7136 ("dmaengine: imx-dma: fix callback path in tasklet").
> But after commit 4cd13c21b207 ("softirq: Let ksoftirqd do its job")
> things got worse, since possible delay between tasklet_schedule()
> from DMA irq handler and actual tasklet function execution got bigger.
> And that gave more time for new DMA request to be submitted and
> to be put into "ld_queue" list.
>
> It has been noticed that DMA issue is causing problems for "mxc-mmc"
> driver. While stressing the system with heavy network traffic and
> writing/reading to/from sd card simultaneously the timeout may happen:
>
> 10013000.sdhci: mxcmci_watchdog: read time out (status = 0x30004900)
>
> That often lead to file system corruption.
Applied and tagged to stable, thanks
--
~Vinod
