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Message-ID: <cac552ce70a747f078738a7167f0a75bc52fac7c.camel@sipsolutions.net>
Subject: Re: [PATCH net] mac80211: mesh: fix mesh_pathtbl_init() error path
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Eric Dumazet <eric.dumazet@gmail.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
Cc:     netdev <netdev@vger.kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        syzbot <syzkaller@googlegroups.com>,
        linux-wireless@vger.kernel.org
Date:   Fri, 04 Dec 2020 17:26:27 +0100
In-Reply-To: <20201204162428.2583119-1-eric.dumazet@gmail.com> (sfid-20201204_172435_837291_23D69393)
References: <20201204162428.2583119-1-eric.dumazet@gmail.com>
         (sfid-20201204_172435_837291_23D69393)
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On Fri, 2020-12-04 at 08:24 -0800, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> If tbl_mpp can not be allocated, we call mesh_table_free(tbl_path)
> while tbl_path rhashtable has not yet been initialized, which causes
> panics.

Thanks Eric!

I was going to ask how you ran into this ...

> Reported-by: syzbot <syzkaller@googlegroups.com>

Until I saw this - but doesn't syzbot normally want a
"syzbot+somehashid@..." as the reported-by?


> --- a/net/mac80211/mesh_pathtbl.c
> +++ b/net/mac80211/mesh_pathtbl.c
> @@ -60,6 +60,7 @@ static struct mesh_table *mesh_table_alloc(void)
>  	atomic_set(&newtbl->entries,  0);
>  	spin_lock_init(&newtbl->gates_lock);
>  	spin_lock_init(&newtbl->walk_lock);
> +	rhashtable_init(&newtbl->rhead, &mesh_rht_params);
>  
>  	return newtbl;
>  }
> @@ -773,9 +774,6 @@ int mesh_pathtbl_init(struct ieee80211_sub_if_data *sdata)
>  		goto free_path;
>  	}
>  
> -	rhashtable_init(&tbl_path->rhead, &mesh_rht_params);
> -	rhashtable_init(&tbl_mpp->rhead, &mesh_rht_params);
> 

Hmm. There were two calls, now there's only one? Is that a bug, or am I
missing something?

johannes