On Thu, Feb 13, 2014 at 10:39:01AM +0100, Linus Walleij wrote: > 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: [email protected] > Reported-by: Dan Carpenter <[email protected]> > Signed-off-by: Linus Walleij <[email protected]>
Applied, thanks -- ~Vinod > --- > drivers/dma/ste_dma40.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > 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; > -- > 1.8.5.3 > -- -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
