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