Re: [PATCH] function mana_hwc_create_wq leaks memory

Hi Dexuan,

Thanks for the feedback.

You are right saying ‘mana_hwc_destroy_wq' free’s up the queue. 

However for example if  function 'mana_hwc_alloc_dma_buf' fails it will goto ‘out' and  call  ‘mana_hwc_destroy_wq', the value 'hwc_wq->gdma_wq' is still not assigned at this point. In the  ‘mana_hwc_destroy_wq' function i see it checks for 'hwc_wq->gdma_wq' before calling, ‘mana_gd_destroy_queue', which makes me think queue is still not freed.

Please let me know if i am missing something.

Regards,
/Dhiraj

On 10 Jun 2021, at 18:28, Dexuan Cui [off-list ref] wrote:

quoted

From: Dexuan Cui <decui@microsoft.com>
Sent: Thursday, June 10, 2021 10:18 AM
...

quoted

diff --git a/drivers/net/ethernet/microsoft/mana/hw_channel.c

b/drivers/net/ethernet/microsoft/mana/hw_channel.c
index 1a923fd99990..4aa4bda518fb 100644

--- a/drivers/net/ethernet/microsoft/mana/hw_channel.c
+++ b/drivers/net/ethernet/microsoft/mana/hw_channel.c

@@ -501,8 +501,10 @@ static int mana_hwc_create_wq(struct

hw_channel_context *hwc,
	*hwc_wq_ptr = hwc_wq;
	return 0;
out:
-	if (err)
+	if (err) {

Here the 'err' must be non-zero. Can you please remove this 'if'?

quoted

+		kfree(queue);
		mana_hwc_destroy_wq(hwc, hwc_wq);
+	}
	return err;
}

Reviewed-by: Dexuan Cui <decui@microsoft.com>

Hi Dhiraj,
I checked the code again and it looks like your patch is actually
unnecessary as IMO there is no memory leak here: the 'queue'
pointer is passed to mana_hwc_destroy_wq() as hwc_wq->gdma_wq,
and is later freed in mana_gd_destroy_queue() ->
mana_gd_destroy_queue().

The 'if' test can be removed as the 'err's is always non-zero there.

Thanks,
Dexuan