When we have a bloated stack it is likely that it ends up making an
invalid memory access that causes a page fault. Take this case into
account in the page fault code.
---
diff -urNp linux-2.6.15-rc2/arch/i386/mm/fault.c
linux-2.6.15-rc2-sov/arch/i386/mm/fault.c
--- linux-2.6.15-rc2/arch/i386/mm/fault.c 2005-11-29 01:46:34.000000000
+0900
+++ linux-2.6.15-rc2-sov/arch/i386/mm/fault.c 2005-11-29
01:48:21.000000000 +0900
@@ -245,6 +245,11 @@ fastcall void __kprobes do_page_fault(st
local_irq_enable();
tsk = current;
+ /* We may have invalid '*current' due to a stack overflow. */
+ if (!virt_addr_valid(tsk)) {
+ printk("do_page_fault: Discarding invalid 'current' struct
task_struct * = 0x%p\n", tsk);
+ tsk = NULL;
+ }
si_code = SEGV_MAPERR;
@@ -271,7 +276,14 @@ fastcall void __kprobes do_page_fault(st
goto bad_area_nosemaphore;
}
- mm = tsk->mm;
+ mm = NULL;
+ /* We may have invalid 'tsk' due to a i386 stack overflow */
+ if (tsk)
+ mm = tsk->mm;
+ if (mm && !virt_addr_valid(mm)) {
+ printk("do_page_fault: Discarding invalid current->mm struct
mm_struct * = 0x%p\n", mm);
+ mm = NULL;
+ }
/*
* If we're in an interrupt, have no user context or are running in an