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Subject: Re: [PATCH] cfg80211: free the object allocated in
 wiphy_apply_custom_regulatory
From:   Johannes Berg <johannes@sipsolutions.net>
To:     Dongliang Mu <mudongliangabcd@gmail.com>,
        Kalle Valo <kvalo@codeaurora.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Luca Coelho <luciano.coelho@intel.com>,
        Ilan Peer <ilan.peer@intel.com>
Cc:     syzbot+1638e7c770eef6b6c0d0@syzkaller.appspotmail.com,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Fri, 23 Jul 2021 10:37:45 +0200
In-Reply-To: <20210723050919.1910964-1-mudongliangabcd@gmail.com>
References: <20210723050919.1910964-1-mudongliangabcd@gmail.com>
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On Fri, 2021-07-23 at 13:09 +0800, Dongliang Mu wrote:
> The commit beee24695157 ("cfg80211: Save the regulatory domain when
> setting custom regulatory") forgets to free the newly allocated regd
> object.

Not really? It's not forgetting it, it just saves it?

+       new_regd = reg_copy_regd(regd);
+       if (IS_ERR(new_regd))
+               return;
+
+       tmp = get_wiphy_regdom(wiphy);
+       rcu_assign_pointer(wiphy->regd, new_regd);
+       rcu_free_regdom(tmp);

> Fix this by freeing the regd object in the error handling code and
> deletion function - mac80211_hwsim_del_radio.

This can't be right - the same would affect all other users of that
function, no?

Perhaps somewhere we have a case where wiphy->regd is leaked, but than
that should be fixed more generally in cfg80211?

johannes