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Date: Sun, 17 Aug 2014 23:37:11 -0500
Message-ID: <CA+55aFwUJLZUi4wDKwiX1XAht=H9exmvUD5P_aNHK9=XBSixjA@mail.gmail.com> (sfid-20140818_063725_542530_B901C39A)
Subject: Re: More wireless problems..
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Johannes Berg <johannes.berg@intel.com>,
	Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
	Michal Kazior <michal.kazior@tieto.com>
Cc: Intel Linux Wireless <ilw@linux.intel.com>,
	"John W. Linville" <linville@tuxdriver.com>,
	Linux Wireless List <linux-wireless@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>
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Sender: linux-wireless-owner@vger.kernel.org

On Sun, Aug 17, 2014 at 11:01 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
>   BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
>   IP: ieee80211_vif_use_reserved_switch+0x71c/0xb00 [mac80211]

Looking at the Code: line and the code generation for that function,
this *looks* to be this code:

                        list_del(&sdata->reserved_chanctx_list);
                        list_move(&sdata->assigned_chanctx_list,
                                  &new_ctx->assigned_vifs);
                        sdata->reserved_chanctx = NULL;

in ieee80211_vif_use_reserved_switch(), where "new_ctx" is NULL, so
the "list_move()" ends up oopsing. But maybe I screwed up the
analysis, I don't know the code.

Looks like that is all-new code introduced by commit 5bcae31d9cb1
("mac80211: implement multi-vif in-place reservations")

And doesn't look at all IWL-specific. Adding Michal Kazior to the list
of people.

                Linus