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authorLinus Walleij <linus.walleij@linaro.org>2014-02-13 10:39:01 +0100
committerVinod Koul <vinod.koul@intel.com>2014-02-17 14:06:58 +0530
commite9baa9d9d520fb0e24cca671e430689de2d4a4b2 (patch)
tree2213cad96b18839d3c86324d8937fc279bc8746c /drivers/dma
parentb28a960c42fcd9cfc987441fa6d1c1a471f0f9ed (diff)
downloadlinux-e9baa9d9d520fb0e24cca671e430689de2d4a4b2.tar.bz2
dma: ste_dma40: don't dereference free:d descriptor
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. Cc: stable@vger.kernel.org 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>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/ste_dma40.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 00a2de957b23..bf18c786ed40 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -1641,6 +1641,7 @@ 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;
@@ -1668,6 +1669,7 @@ 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;
@@ -1690,7 +1692,7 @@ 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)
callback(callback_param);
return;