help with GPF on 5.4-STABLE

Peter Wemm peter at
Fri May 20 16:05:37 PDT 2005

On Friday 20 May 2005 01:59 pm, Doug White wrote:
> kern.timeout.c line 530 is
> 530         mtx_unlock_spin(&callout_lock);
> I'm not sure what in there would generate a GPF. 

Allowing an invalid address to reach the AGU (address generation unit) 
will cause a GPF with no specific details.  Its a real pain in the butt 
because it should cause a SIGBUS with the bad address in siginfo.  But 
since GPF doesn't tell us anything useful, we can't do this.   

Anyway...  the usual cause is that the upper 16 bits are not all 0's or 
all 1's.  ie: its a reference outside the sign extended 48 bit virtual 
address space.  The disassemble that you asked for will show us which 
register we should be looking at for what the actual address was..
Peter Wemm - peter at; peter at; peter at
"All of this is for nothing if we don't go to the stars" - JMS/B5

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