Understanding panic and exit in the kernel

[Charlie Martin]

On 2011-09-07 12:53, mdf at FreeBSD.org wrote:
>> For my immediate purposes, I'd be happy with any way in which I could
>> >  brutally kill the kernel and force it to the debugger, say by replacing the
>> >  panic call with a printf followed by "1/0;".  But I'm a little confused by
>> >  the panic.c code -- it prints the arguments using a var_args, and then calls
>> >  "exit(1);'
> What file are you looking in?  The kernel panic() is in
> sys/kern/kern_shutdown.c, not sys/boot/common/panic.c.  It will
> optionally call kdb_enter_why() and then boot().

Bingo, that's got to help.  This makes a lot more sense.

> Do you have the debug.debugger_on_panic sysctl set to 1?

Yes -- and panic does so *except* in the version with those changes to 
queue.h.

> Thanks,
> matthew
>

-- 

Charles R. (Charlie) Martin
Senior Software Engineer
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