Netlink Memory Leak Issue

Netlink Memory Leak Issue

[Saurabh8 Jain]

Hi,

I would like to know the memory usage that happens between user space and kernel space communication. Communication happens via generic netlink library and we need to register doit and dump functions.

I was going through function "nl80211_set_mesh_params" in "net/wireless/nl80211.c" which receives values of mesh parameters. In this function skb is passed but it is never used and the skb is not freed. I saw other functions also which receives messages from user space but no memory is released for skb.

Where is this memory getting free? Do I need to free this memory?

When I executed iw commands to set few values in loop.  I saw there is drop in free memory of "top" command. I am working on compatwireless-2010-06-27.


Thanks,
Saurabh Jain

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Re: Netlink Memory Leak Issue

[Johannes Berg]

On Thu, 2010-12-16 at 11:01 +0530, Saurabh8 Jain wrote:
> Hi,
> 
> I would like to know the memory usage that happens between user space
> and kernel space communication. Communication happens via generic
> netlink library and we need to register doit and dump functions.

Yes.

> I was going through function "nl80211_set_mesh_params" in
> "net/wireless/nl80211.c" which receives values of mesh parameters. In
> this function skb is passed but it is never used and the skb is not
> freed. I saw other functions also which receives messages from user
> space but no memory is released for skb.

> Where is this memory getting free? Do I need to free this memory?

Look at net/netlink/ -- we don't need to handle that.

> When I executed iw commands to set few values in loop.  I saw there is
> drop in free memory of "top" command. I am working on
> compatwireless-2010-06-27.

You're seriously taking "top" for a measurement? That's like the worst
possible way to measure memory usage.

johannes

Re: Netlink Memory Leak Issue

[jpo234]

Saurabh8 Jain <saurabh8.jain@...> writes:
> Where is this memory getting free? Do I need to free this memory?
> 
> When I executed iw commands to set few values in loop.  I saw there is drop in
free memory of "top" command. I am
> working on compatwireless-2010-06-27.

Do you really think that a perceived memory leak in libnl could explain this?
This can't be true. If you run iw in a shell loop it will terminate after every
invocation and the kernel will free all associated resources.

Regards
  Joerg