dmaengine: at_hdmac: fix memory leak in at_dma_xlate()
From: Mario Forner <hidden>
Date: 2018-11-30 10:07:48
Also in:
linux-arm-kernel, linux-serial, lkml, stable
Am Dienstag, 27. November 2018, 17:06:34 CET schrieb Richard Genoud:
The leak was found when opening/closing a serial port a great number of
time, increasing kmalloc-32 in slabinfo.
Each time the port was opened, dma_request_slave_channel() was called.
Then, in at_dma_xlate(), atslave was allocated with devm_kzalloc() and
never freed. (Well, it was free at module unload, but that's not what we
want).
So, here, kzalloc is more suited for the job since it has to be freed in
atc_free_chan_resources().
Cc: stable@vger.kernel.org
Fixes: bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")
Reported-by: Mario Forner <redacted>
Suggested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Genoud <redacted>After testing I installed an updated kernel on a production machine, which worked fine. The memory leak has been repaired successfully. There have been no adverse side-effects. Thank you for providing the patch.
quoted hunk ↗ jump to hunk
--- drivers/dma/at_hdmac.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 7cbac6e8c113..1b7f0ca0d5cd 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c@@ -1641,6 +1641,12 @@ static void atc_free_chan_resources(struct dma_chan *chan) atchan->descs_allocated = 0; atchan->status = 0; + /* + * Free atslave allocated in at_dma_xlate() + */ + kfree(chan->private); + chan->private = NULL; + dev_vdbg(chan2dev(chan), "free_chan_resources: done\n"); }@@ -1675,7 +1681,7 @@ static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec, dma_cap_zero(mask); dma_cap_set(DMA_SLAVE, mask); - atslave = devm_kzalloc(&dmac_pdev->dev, sizeof(*atslave), GFP_KERNEL); + atslave = kzalloc(sizeof(*atslave), GFP_KERNEL); if (!atslave) return NULL;