diff options
authorLinus Walleij <linus.walleij@linaro.org>2014-02-13 10:39:01 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-03-06 21:30:13 -0800
commit102544b7f13be7023db6f6447bf67cdafc239f24 (patch)
parentf7caf9429406422de57e1b65284f47d8e5cbf7ae (diff)
dma: ste_dma40: don't dereference free:d descriptor
commit e9baa9d9d520fb0e24cca671e430689de2d4a4b2 upstream. It appears that in the DMA40 driver the DMA tasklet will very often dereference memory for a descriptor just free:d from the DMA40 slab. Nothing happens because no other part of the driver has yet had a chance to claim this memory, but it's really nasty to dereference free:d memory, so let's check the flag before the descriptor is free and store it in a bool variable. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 71bf4ec300ea..ca78044df4b5 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -1587,6 +1587,7 @@ static void dma_tasklet(unsigned long data)
struct d40_chan *d40c = (struct d40_chan *) data;
struct d40_desc *d40d;
unsigned long flags;
+ bool callback_active;
dma_async_tx_callback callback;
void *callback_param;
@@ -1614,6 +1615,7 @@ static void dma_tasklet(unsigned long data)
/* Callback to client */
+ callback_active = !!(d40d->txd.flags & DMA_PREP_INTERRUPT);
callback = d40d->txd.callback;
callback_param = d40d->txd.callback_param;
@@ -1636,7 +1638,7 @@ static void dma_tasklet(unsigned long data)
spin_unlock_irqrestore(&d40c->lock, flags);
- if (callback && (d40d->txd.flags & DMA_PREP_INTERRUPT))
+ if (callback_active && callback)