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Subject[PATCH 3.16.y-ckt 125/144] dmaengine: edma: fix memory leak when terminating running transfers
Date
3.16.7-ckt10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Petr Kulhavy <petr@barix.com>

commit 5ca9e7ce6eebec53362ff779264143860ccf68cd upstream.

If edma_terminate_all() was called while a transfer was running (i.e. after
edma_execute() but before edma_callback()) the echan->edesc was not freed.

This was due to the fact that a running transfer is on none of the
vchan lists: desc_submitted, desc_issued, desc_completed (edma_execute()
removes it from the desc_issued list), so the vchan_dma_desc_free_list()
called at the end of edma_terminate_all() didn't find it and didn't free it.

This bug was found on an AM1808 based hardware (very similar to da850evm,
however using the second MMC/SD controller), where intense operations on the SD
card wasted the device 128MB RAM within a couple of days.

Peter Ujfalusi:
The issue is even more severe since it affects cyclic (audio) transfers as
well. In this case starting/stopping audio will results memory leak.

Signed-off-by: Petr Kulhavy <petr@barix.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
CC: <linux-omap@vger.kernel.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
drivers/dma/edma.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index d08c4dedef35..3c58df963e06 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -256,6 +256,12 @@ static int edma_terminate_all(struct edma_chan *echan)
* echan->edesc is NULL and exit.)
*/
if (echan->edesc) {
+ /*
+ * free the running request descriptor
+ * since it is not in any of the vdesc lists
+ */
+ edma_desc_free(&echan->edesc->vdesc);
+
echan->edesc = NULL;
edma_stop(echan->ch_num);
}

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