git.openwrt.org Git - openwrt/openwrt.git/blob

   1 From 4967ec844a52498af050b1176fedeca37aca111e Mon Sep 17 00:00:00 2001
   2 From: Robin Gong <yibin.gong@nxp.com>
   3 Date: Tue, 16 Oct 2018 01:06:29 +0800
   4 Subject: [PATCH] MLK-19931-1: dmaengine: fsl-edma-v3: fix potential kernel
   5  crash in cyclic
   6
   7   There is one potential race condition in virt-dma framework as below:
   8 terminate dma channel after the last dma done interrupt, but before
   9 vchan_complete tasklet scheduled, thus the free-ed 'vd' (free in
  10 fsl_edma3_terminate_all) maybe still be touched in vchan_complete()
  11 which cause NULL pointer crash.
  12   Kernel community noticed this issue and fix it at virt-dma level:
  13 https://patchwork.kernel.org/patch/10057791/. To avoid backport too
  14 much patches, set 'vc->cyclic = NULL' in terminate dma channel
  15 interfaces to fix such issue easily.
  16
  17 Signed-off-by: Robin Gong <yibin.gong@nxp.com>
  18 Acked-by: Fugang Duan <fugang.duan@nxp.com>
  19 (cherry picked from commit 18c9083826400a2ef731496391a0b5e71d461a5f)
  20 ---
  21  drivers/dma/fsl-edma-v3.c | 1 +
  22  1 file changed, 1 insertion(+)
  23
  24 --- a/drivers/dma/fsl-edma-v3.c
  25 +++ b/drivers/dma/fsl-edma-v3.c
  26 @@ -285,6 +285,7 @@ static int fsl_edma3_terminate_all(struc
  27         fsl_chan->edesc = NULL;
  28         fsl_chan->idle = true;
  29         fsl_chan->used = false;
  30 +       fsl_chan->vchan.cyclic = NULL;
  31         vchan_get_all_descriptors(&fsl_chan->vchan, &head);
  32         spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
  33         vchan_dma_desc_free_list(&fsl_chan->vchan, &head);