kern/117820: rum related kernel panic

[Christian Spiel]

>Number:         117820
>Category:       kern
>Synopsis:       rum related kernel panic
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Nov 04 16:50:01 UTC 2007
>Closed-Date:
>Last-Modified:
>Originator:     Christian Spiel
>Release:        7.0-CURRENT
>Organization:
Vienna University of Technology
>Environment:
amd64
>Description:
Using the rum driver with WPA enabled the kernel panics within a few minutes when downloading stuff.

I have backtraced the problem using the coredump and kgdb. It shows that in if_rum.c at line 842 a null pointer dereference occurs.

842:        if (data->m->m_flags & M_TXCB)
                    843:                ieee80211_process_callback(data->ni, data->m,
                    844:                        status == USBD_NORMAL_COMPLETION ? 0 : ETIMEDOUT);

data is NULL because the function rum_txeof was called with priv==NULL. 
>How-To-Repeat:
Easily repeatable
>Fix:
I have added a check against null pointer in this function and it improves the stability of the system considerably although that is of course not the correct solution.

>Release-Note:
>Audit-Trail:
>Unformatted: