target/linux/layerscape/patches-5.4/806-dma-0010-MLK-16437-dma-fsl-edma-v3-fix-kernel-crash-while-edm.patch

   1 From e0d0cdff101b2f00ce1fd420522bd22bb6eebd9f Mon Sep 17 00:00:00 2001
   2 From: Robin Gong <yibin.gong@nxp.com>
   3 Date: Wed, 13 Sep 2017 16:39:49 +0800
   4 Subject: [PATCH] MLK-16437: dma: fsl-edma-v3: fix kernel crash while edma
   5  interrupt trigger after channel disabled
   6
   7 edma interrupt may come after channel terminated, so should ignore
   8 interrupts, else kernel crash as below since fsl_chan->edesc set
   9 to NULL when terminate.
  10
  11  606.837306] Unable to handle kernel NULL pointer dereference at virtual address 00000060
  12 [  606.845411] pgd = ffff000009295000
  13 [  606.848814] [00000060] *pgd=00000008bfffe003[  606.852906] , *pud=00000008bfffd003
  14  , *pmd=0000000000000000[  606.858395]
  15 [  606.859885] Internal error: Oops: 96000006 1 PREEMPT SMP
  16 [  606.865460] Modules linked in:
  17 [  606.868522] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.11-03371-g9904ea0 #42
  18 [  606.875832] Hardware name: Freescale i.MX8QXP LPDDR4 ARM2 (DT)
  19 [  606.881662] task: ffff000009120680 task.stack: ffff000009110000
  20 [  606.887588] PC is at fsl_edma3_tx_handler+0x50/0x150
  21
  22 Signed-off-by: Robin Gong <yibin.gong@nxp.com>
  23 Tested-by: Daniel Baluta <daniel.baluta@nxp.com>
  24 (cherry picked from commit 625afad5a0900bc3e3288510f61647b1d891a5a4)
  25 ---
  26  drivers/dma/fsl-edma-v3.c | 5 +++++
  27  1 file changed, 5 insertions(+)
  28
  29 --- a/drivers/dma/fsl-edma-v3.c
  30 +++ b/drivers/dma/fsl-edma-v3.c
  31 @@ -689,6 +689,11 @@ static irqreturn_t fsl_edma3_tx_handler(
  32         writel(1, base_addr + EDMA_CH_INT);
  33
  34         spin_lock(&fsl_chan->vchan.lock);
  35 +
  36 +       /* Ignore this interrupt since channel has been disabled already */
  37 +       if (!fsl_chan->edesc)
  38 +               return IRQ_HANDLED;
  39 +
  40         if (!fsl_chan->edesc->iscyclic) {
  41                 fsl_edma3_get_realcnt(fsl_chan);
  42                 list_del(&fsl_chan->edesc->vdesc.node);