[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20140308010612.928817719@linuxfoundation.org>
Date: Fri, 7 Mar 2014 17:07:37 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Dan Carpenter <dan.carpenter@...cle.com>,
Linus Walleij <linus.walleij@...aro.org>,
Vinod Koul <vinod.koul@...el.com>
Subject: [PATCH 3.4 41/99] dma: ste_dma40: dont dereference free:d descriptor
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Linus Walleij <linus.walleij@...aro.org>
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@...cle.com>
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Vinod Koul <vinod.koul@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/dma/ste_dma40.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -1409,6 +1409,7 @@ static void dma_tasklet(unsigned long da
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;
@@ -1432,6 +1433,7 @@ static void dma_tasklet(unsigned long da
}
/* Callback to client */
+ callback_active = !!(d40d->txd.flags & DMA_PREP_INTERRUPT);
callback = d40d->txd.callback;
callback_param = d40d->txd.callback_param;
@@ -1456,7 +1458,7 @@ static void dma_tasklet(unsigned long da
spin_unlock_irqrestore(&d40c->lock, flags);
- if (callback && (d40d->txd.flags & DMA_PREP_INTERRUPT))
+ if (callback_active && callback)
callback(callback_param);
return;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists