observed memory leak in wpa_supplicant

[Naveen Singh]

On Wed, Feb 3, 2016 at 4:20 AM, Jouni Malinen <j at w1.fi> wrote:
> On Wed, Jan 27, 2016 at 10:06:32PM -0800, Naveen Singh wrote:
>> We have been running some stress test of sending a deauth with reason
>> code 6 and 7 from an AP to an associated client and monitoring the
>> memory usage of wpa_supplicant. In our setup wpa_supplicant talks to
>> connman over dbus. Running this stress test reveals memory leak in wpa
>> supplicant (memory usage of wpa supplicant keeps on growing).
>
> Have you checked that this is actually a real memory leak? For example,
> run wpa_supplicant under valgrind and see whether such memory gets freed
> when the process exits.

Yes I ran valgrind. Valgrind reported this memory as still reachable
as it is lying in list. It is ideally not a leak because all the
pointers point to same network,
>
>> For connection after getting disconnected connman does "AddNetwork"
>> DBUS call to the previously connected SSID. This ends up causing
>> memory to be allocated for struct wpa_ssid (os_zalloc called). At this
>> time there is already a structure allocated for same SSID as a result
>> of previous connection. Every connection ends up creating a memory
>> which is never freed.
>
> Are you sure it is not freed when wpa_supplicant process terminates? All
> the added network blocks should be freed at that point in time..
When supplicant terminates or is restarted it reclaims all the memory.
>
>> This surely causes memory usage of wpa_supplicant to go up. Should not
>> we be allocating memory only if that profile (for that SSID does not
>> exist?)
>
> Memory is allocated only if a new profile is added. There can be
> multiple profiles for a single SSID.
I guess that is intent but surely that is not happening. We are
allocating memory for same profile (same SSID and security)
>
>> I am talking about this function:
>> struct wpa_ssid * wpa_config_add_network(struct wpa_config *config)
>
> This needs to add a new network profile and allocate memory for it.
>
> If you do not want more memory to be used, it is responsibility of the
> program managing wpa_supplicant (either through the control interface or
> through D-Bus) to re-use existing network profiles or remove profiles
> they have added.
I guess that is the solution. I am working on a patch to remove the
network once it is not needed. It is slightly tricky to do so because
we just do not want to remove the network when wpa_supplicant is
trying to connect to same network.
>
> --
> Jouni Malinen                                            PGP id EFC895FA