On Toradex Colibri VF50 (Vybrid VF5xx) with fsl-edma driver NULL pointer exception happens occasionally on serial output initiated by login timeout.
This was reproduced only if kernel was built with significant debugging options and EDMA driver is used with serial console.
Issue looks like a race condition between interrupt handler fsl_edma_tx_handler() (called as a result of fsl_edma_xfer_desc()) and terminating the transfer with fsl_edma_terminate_all().
The fsl_edma_tx_handler() handles interrupt for a transfer with already freed edesc and idle==true.
The mcf-edma driver shares design and lot of code with fsl-edma. It looks like being affected by same problem. Fix this pattern the same way as fix for fsl-edma driver.
Fixes: e7a3ff92eaf1 ("dmaengine: fsl-edma: add ColdFire mcf5441x edma support") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski krzk@kernel.org
---
Not tested on HW. --- drivers/dma/mcf-edma.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/drivers/dma/mcf-edma.c b/drivers/dma/mcf-edma.c index e15bd15a9ef6..e12b754e6398 100644 --- a/drivers/dma/mcf-edma.c +++ b/drivers/dma/mcf-edma.c @@ -35,6 +35,13 @@ static irqreturn_t mcf_edma_tx_handler(int irq, void *dev_id) mcf_chan = &mcf_edma->chans[ch];
spin_lock(&mcf_chan->vchan.lock); + + if (!mcf_chan->edesc) { + /* terminate_all called before */ + spin_unlock(&mcf_chan->vchan.lock); + continue; + } + if (!mcf_chan->edesc->iscyclic) { list_del(&mcf_chan->edesc->vdesc.node); vchan_cookie_complete(&mcf_chan->edesc->vdesc);