From: Michael Buesch <mb@bu3sch.de>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-wireless@vger.kernel.org
Subject: Weird oops in mac80211's skb_orphan call
Date: Tue, 24 Jun 2008 01:32:21 +0200 [thread overview]
Message-ID: <200806240132.21362.mb@bu3sch.de> (raw)
I have a 100% reproducable oops inside of the skb_orphan
call of mac80211's ieee80211_tx_status function.
I could only reproduce it with the CompactFlash bcm4318 card, yet.
So maybe the it's somehow related to b43's PIO code.
Here's the oops:
http://bu3sch.de/misc/sk_oops.JPG
As you can see, I added some debugging printks.
So let me explain what is going on.
After fireing up wpa_supplicant, ieee80211_tx_status is invoked several times
without crashing. But then suddenly it crashes on the skb_orphan call.
The skb_orphan call will call the skb destructor. You can see the
skb->destructor and skb->sk pointers right above the oops message.
The destructor pointer is assigned to sock_wfree() and the sk pointer is NULL.
So skb_orphan calls skb->destructor with skb->sk as parameter and sock_wfree (which
is the destructor) will dereference skb->sk. That will obviously crash.
Any ideas why skb->sk is NULL while the destructor is not NULL?
They should either be both NULL or not NULL.
--
Greetings Michael.
reply other threads:[~2008-06-23 23:32 UTC|newest]
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