:2007/10/16, Peter Avalos <[EMAIL PROTECTED]>:
:> Just had this one last night:
:>
:> Fatal trap 12: page fault while in kernel mode
:[...]
:> #7 0xc018cb85 in fill_kinfo_proc (p=0xe8c21ba0, kp=0xec319628) at
/usr/src/sys/kern/kern_kinfo.c:66
:
:It looks like p->p_pgrp == NULL.
:
:p_pgrp is checked against NULL in several other places in the kernel
:(and in fbsd too), so a fix could be to do the same in
:fill_kinfo_proc().
:
:However, I don't understand how p_pgrp can be NULL. AFAIU, it is
:inherited from the parent process and set to NULL only when the
:process is about to die (leaveprgp() called from kern_wait() just
:before deleting the proc structure). Could there be some race
:condition?
I thought I fixed that one.
Yes, kinfo_proc can race against an exiting process. An exiting process
will be in a partially deallocated state and p_pgrp could very well be
NULL as of the moment kinfo_proc tries to access it.
-Matt
Matthew Dillon
<[EMAIL PROTECTED]>
