Catch NULL dereferences

PATCH New Samuel Thibault 1 participant 1 message Nov 27, 2007

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Samuel Thibault

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2007-11-27 11:23 UTC #0 lore raw

PATCH 1/1 Catch NULL dereferences

Unmap page 0 (only used early at boot) so as to catch NULL dereferences.

Signed-off-by Samuel Thibault <[email protected]>

extras/mini-os/arch/x86/mm.c +3 -0

diff -r 26e766e0c628 extras/mini-os/arch/x86/mm.c
@@ -270,6 +270,9 @@ void build_pagetable(unsigned long *star
         start_address += PAGE_SIZE;
     }
 
+    if (HYPERVISOR_update_va_mapping(0, (pte_t) {}, UVMF_INVLPG))
+        printk("Unable to unmap page 0\n");
+
     *start_pfn = pt_pfn;
 }