dmaengine: at_hdmac: fix memory leak in at_dma_xlate()
PATCH 1/1 dmaengine: at_hdmac: fix memory leak in at_dma_xlate()
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().
--- drivers/dma/at_hdmac.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
drivers/dma/at_hdmac.c +7 -1
@@ -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 ;
PATCH 1/1 dmaengine: at_hdmac: fix module unloading
of_dma_controller_free() was not called on module onloading. This lead to a soft lockup:
watchdog: BUG: soft lockup - CPU#0 stuck for 23s! Modules linked in: at_hdmac [last unloaded: at_hdmac]
when of_dma_request_slave_channel() tried to call ofdma->of_dma_xlate().
--- drivers/dma/at_hdmac.c | 2 ++ 1 file changed, 2 insertions(+)
drivers/dma/at_hdmac.c +2 -0
@@ -2006,6 +2006,8 @@ static int at_dma_remove(struct platform_device *pdev)struct resource *io;at_dma_off (atdma); +if (pdev->dev.of_node) +of_dma_controller_free (pdev->dev.of_node);dma_async_device_unregister (&atdma->dma_common);dma_pool_destroy (atdma->memset_pool);
Re: [PATCH] dmaengine: at_hdmac: fix module unloading
Quoted 1 line · Richard Genoud
of_dma_controller_free()was not called on module onloading.
s/onloading/unloading
Quoted 8 lines
This lead to a soft lockup:
watchdog: BUG: soft lockup - CPU#0 stuck for 23s! Modules linked in: at_hdmac [last unloaded: at_hdmac]when
of_dma_request_slave_channel()tried to callofdma->of_dma_xlate().Fixes bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")Signed-off-by Richard Genoud <[email protected]>
Thanks
Ludovic
Quoted 17 lines
--- drivers/dma/at_hdmac.c | 2 ++ 1 file changed, 2 insertions(+)drivers/dma/at_hdmac.c +2
-0@@ -2006,6 +2006,8 @@ static int at_dma_remove(struct platform_device *pdev)struct resource *io;at_dma_off (atdma); +if (pdev->dev.of_node) +of_dma_controller_free (pdev->dev.of_node);dma_async_device_unregister (&atdma->dma_common);dma_pool_destroy (atdma->memset_pool);
Re: [PATCH] dmaengine: at_hdmac: fix module unloading
In reply to Richard GenoudQuoted 5 lines · Richard Genoud
of_dma_controller_free()was not called on module onloading. This lead to a soft lockup:watchdog: BUG: soft lockup - CPU#0 stuck for 23s! Modules linked in: at_hdmac [last unloaded: at_hdmac]when
of_dma_request_slave_channel()tried to callofdma->of_dma_xlate().
Applied, thanks
Quoted 10 lines · 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, inat_dma_xlate(), atslave was allocated withdevm_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 inatc_free_chan_resources().
Quoted 6 lines
Fixes bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")Reported-by Mario Forner <[email protected]>Suggested-by Alexandre Belloni <[email protected]>Signed-off-by Richard Genoud <[email protected]>
Thanks for handling this issue.
Ludovic
Quoted 30 lines
--- drivers/dma/at_hdmac.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)drivers/dma/at_hdmac.c +7
-1@@ -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 ;
Quoted 9 lines · 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, inat_dma_xlate(), atslave was allocated withdevm_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 inatc_free_chan_resources().
Applied, thanks
Am Dienstag, 27. November 2018, 17:06:34 CET schrieb Richard Genoud:
Quoted 10 lines
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, inat_dma_xlate(), atslave was allocated withdevm_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 inatc_free_chan_resources().
Quoted 6 lines
Fixes bbe89c8e3d59 ("at_hdmac: move to generic DMA binding")Reported-by Mario Forner <[email protected]>Suggested-by Alexandre Belloni <[email protected]>Signed-off-by Richard Genoud <[email protected]>
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 31 lines
--- drivers/dma/at_hdmac.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)drivers/dma/at_hdmac.c +7
-1@@ -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 ;