Re: [B.A.T.M.A.N.] [PATCH 1/3] batman-adv: fix lockdep splat when doing mcast_free

[Antonio Quartulli <antonio@meshcoding.com>]

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Sven Eckelmann:
> Maybe the relevant parts of the Oops can be added to the commit message:
> 
>     WARNING: CPU: 0 PID: 238 at net/batman-adv/multicast.c:142 batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]()
>     [...]
>     Call Trace:
>      [<ffffffff815fc597>] dump_stack+0x4b/0x64
>      [<ffffffff810b34dc>] warn_slowpath_common+0xbc/0x120
>      [<ffffffffa0024ec5>] ? batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]
>      [<ffffffff810b3705>] warn_slowpath_null+0x15/0x20
>      [<ffffffffa0024ec5>] batadv_mcast_mla_tt_retract+0x94/0x205 [batman_adv]
>      [<ffffffffa00273fe>] batadv_mcast_free+0x36/0x39 [batman_adv]
>      [<ffffffffa0020c77>] batadv_mesh_free+0x7d/0x13f [batman_adv]
>      [<ffffffffa0036a6b>] batadv_softif_free+0x15/0x25 [batman_adv]
>      [...]


I agree

> 
>> I see it calls batadv_tt_local_remove() but this does not really
>> requires the lock. Maybe you wanted to perform *all* the removes before
>> TT could do a commit ? Or is there any other reason?
>>
>> Cheers,
> 
> mcast.mla_list is protected by tt.commit_lock (see batadv_mcast_mla_tt_add,
> batadv_mcast_mla_list_free and batadv_mcast_mla_tt_retract).
> 

ok, this makes sense :)

Simon, I'd suggest you follow Sven's suggestion about adding the
oops/stacktrace and then you can also append my

Acked-by: Antonio Quartulli <antonio@meshcoding.com>

note that this patch is a bugfix, hence it should target maint.

Cheers,


-- 
Antonio Quartulli


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