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saved_proc in exception() may be NULL

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If an exception happens in kernel while the kernel is booting and no processes
are running yet, saved_proc == NULL and priting any process related information
results in dumping rubish.

This check is mostly useful when debugging kernel stuff. Should _never_ happen
on a production kernel.
This commit is contained in:
Tomas Hruby 2009-08-29 19:26:46 +00:00
parent 42f0bf7dda
commit 50473107c2
1 changed files with 18 additions and 9 deletions
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27
kernel/arch/i386/exception.c
View file

@ -163,16 +163,25 @@ struct proc *t;
else
kprintf("\n%s\n", ep->msg);
kprintf("k_reenter = %d ", k_reenter);
kprintf("process %d (%s), ", proc_nr(saved_proc), saved_proc->p_name);
kprintf("pc = %u:0x%x\n", (unsigned) saved_proc->p_reg.cs,
(unsigned) saved_proc->p_reg.pc);
kprintf(
"vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, cs= 0x%x, eflags= 0x%lx\n",
vec_nr, (unsigned long)trap_errno,
(unsigned long)old_eip, old_cs, (unsigned long)old_eflags);
proc_stacktrace(saved_proc);
minix_panic("exception in a kernel task", saved_proc->p_endpoint);
/* TODO should we enable this only when compiled for some debug mode? */
if (saved_proc) {
kprintf("process %d (%s), ", proc_nr(saved_proc), saved_proc->p_name);
kprintf("pc = %u:0x%x\n", (unsigned) saved_proc->p_reg.cs,
(unsigned) saved_proc->p_reg.pc);
kprintf("vec_nr= %d, trap_errno= 0x%lx, eip= 0x%lx, "
"cs= 0x%x, eflags= 0x%lx\n",
vec_nr, (unsigned long)trap_errno,
(unsigned long)old_eip, old_cs,
(unsigned long)old_eflags);
proc_stacktrace(saved_proc);
minix_panic("exception in a kernel task", saved_proc->p_endpoint);
}
else {
/* in an early stage of boot process we don't have processes yet */
minix_panic("exception in kernel while booting", NO_NUM);
}
}
/*===========================================================================*