MLK-19931-1: dmaengine: fsl-edma-v3: fix potential kernel crash in cyclic

  There is one potential race condition in virt-dma framework as below:
terminate dma channel after the last dma done interrupt, but before
vchan_complete tasklet scheduled, thus the free-ed 'vd' (free in
fsl_edma3_terminate_all) maybe still be touched in vchan_complete()
which cause NULL pointer crash.
  Kernel community noticed this issue and fix it at virt-dma level:
https://patchwork.kernel.org/patch/10057791/. To avoid backport too
much patches, set 'vc->cyclic = NULL' in terminate dma channel
interfaces to fix such issue easily.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>

diff --git a/drivers/dma/fsl-edma-v3.c b/drivers/dma/fsl-edma-v3.c
index f74f46a..47c7a17 100644 (file)
--- a/drivers/dma/fsl-edma-v3.c
+++ b/drivers/dma/fsl-edma-v3.c
@@ -288,6 +288,7 @@ static int fsl_edma3_terminate_all(struct dma_chan *chan)
        fsl_chan->edesc = NULL;
        fsl_chan->idle = true;
        fsl_chan->used = false;
+       fsl_chan->vchan.cyclic = NULL;
        vchan_get_all_descriptors(&fsl_chan->vchan, &head);
        spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
        vchan_dma_desc_free_list(&fsl_chan->vchan, &head);