> Is this the first OOPS it prints out? I don't think so. I am
> very sure it printed out messages from die_if_kernel first and
> we need that initial OOPS to diagnose this bug and fix it.
>
> All the rest of the OOPS messages are useless and won't tell
> us what the real problem is.
> Later,
> David S. Miller
Bad news about recursive Oops is that too often the system
cannot continue and oopsen never reach /var/log/messages.
This problem was so common on sparc(32) that I run all my
kernels with the attached patch. I think an application
of a similar change should be mandatory if you are insterested
in any sort of debugging.
The alternative is to use a serial console, captured at all times.
--Pete
diff -u -r1.63 traps.c
--- arch/sparc/kernel/traps.c 2000/06/04 06:23:52 1.63
+++ arch/sparc/kernel/traps.c 2000/06/26 18:19:10
@@ -114,18 +116,23 @@
* bound in case our stack is trashed and we loop.
*/
while(rw &&
- count++ < 30 &&
+ count++ < 10 && /* P3 30 */
(((unsigned long) rw) >= PAGE_OFFSET) &&
!(((unsigned long) rw) & 0x7)) {
printk("Caller[%08lx]\n", rw->ins[7]);
rw = (struct reg_window *)rw->ins[6];
}
}
+#if 0
printk("Instruction DUMP:");
instruction_dump ((unsigned long *) regs->pc);
if(regs->psr & PSR_PS)
do_exit(SIGKILL);
do_exit(SIGSEGV);
+#else
+ printk("Looping...");
+ for (;;) { }
+#endif
}
void do_hw_interrupt(unsigned long type, unsigned long psr, unsigned long pc)
Index: arch/sparc/mm/fault.c
===================================================================
RCS file: /vger-cvs/linux/arch/sparc/mm/fault.c,v
retrieving revision 1.116
diff -u -r1.116 fault.c
--- arch/sparc/mm/fault.c 2000/05/03 06:37:03 1.116
+++ arch/sparc/mm/fault.c 2000/06/26 18:19:11
@@ -146,11 +146,15 @@
printk(KERN_ALERT "Unable to handle kernel paging request "
"at virtual address %08lx\n", address);
}
+ if (tsk->active_mm == NULL) {
+ printk(KERN_ALERT "tsk->active_mm = NULL\n");
+ } else {
printk(KERN_ALERT "tsk->{mm,active_mm}->context = %08lx\n",
(tsk->mm ? tsk->mm->context : tsk->active_mm->context));
printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %08lx\n",
(tsk->mm ? (unsigned long) tsk->mm->pgd :
(unsigned long) tsk->active_mm->pgd));
+ }
die_if_kernel("Oops", regs);
}
-
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