Kernel Panic in 2.2.x

Hawkins Jeffrey-CJH016 Jeffrey.F.Hawkins at
Sat May 31 02:11:16 EST 2003

Follow-up to my Kernel Panic Investigations, it appears
that the Process as having "tss->regs" as NULL, during
the execution of "ps" command, is a modprobe being performed
by the Kernel for attempting to Load net-pf-10 Module
(IPV6 Packet Filter).

> -----Original Message-----
> From: Hawkins Jeffrey-CJH016
> Sent: Thursday, May 29, 2003 2:05 PM
> To: linuxppc-dev at
> Subject: Kernel Panic in 2.2.x
> Request for Info/Feedbak....
> With a Standard 2.2.17 Kernel, with some Proprietary Hardware Drivers,
> we intermittently encounter a Kernel Panic due to Reference to a NULL
> Pointer.  I have isolated the NULL Reference to the "procfs" Support.
> In particular, in "array.c", the "get_stat" function, with usage
> of the KSTK_EIP and KSTK_ESP Macros.  The NULL access is due to
> the "regs" pointer in the "tss" structure being NULL.  My theory
> is there is a race condition with procfs access and a process
> terminating at the same time.  At the time of a our failure, a
> Process is terminating (a Daemon Restart induced by our Application),
> as well as,  one of our Application's is performing Raw Socket
> I/O for Network Monitoring -- the strange thing is that if we
> remove the Raw Socket Functionality we can not get the Failure
> to occur.
> I noticed in the 2.4.x Tree the KSTK_ Macros have been modified
> to check for NULL. Does anybody know if this was the reason for
> the change.  Looking at the Kernel List Archives, it seems the
> change was for "init" issues in "BootX"?
> Also, reviewing the Kernel List Archives, I noticed in 2.2.x
> there was a race condition with "procfs" access, but related
> to the MM Stats/Params of a Process, not the TSS Registers.
> Anybody have any insight into this Issue?
> Also, insight into how the tss->regs is utilized and updated
> would be appreciated.  I have started reviewing the PPC Specific
> Kernel Code to get this info on the Task Switching Implementation,
> but I thought maybe someone here could give me some insight, or
> direct me to a Book/URL/Reference that has this type of information.
> With respect to responses, please don't say go to the 2.4.x Kernel
> as a solution for the Issue....:)  This is in our plans, but
> at this time,
> we are locked into the 2.2 Kernel due to Proprietary Hardware Driver
> Support.  For the short term, I just want to identify the true root
> cause (to appease the Management Gods), and to possibly implement
> a short term fix until we migrate to the 2.4.x or 2.6 Kernel.
> Jeff

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