Fix for the x86_64 "vm -p" command to properly emulate the kernel's

pte_present() function, which checks for either _PAGE_PRESENT or _PAGE_PROTNONE to be set. Without the patch, user pages whose PTE does not have _PAGE_PRESENT bit set are misconstrued as SWAP pages with an "(unknown swap location") along with a bogus OFFSET value. ([email protected])
crash-utility · Apr 25, 2016 · aad859e · aad859e
1 parent 1230512
commit aad859e
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/x86_64.c b/x86_64.c
@@ -1431,7 +1431,8 @@ x86_64_uvtop_level4(struct task_context *tc, ulong uvaddr, physaddr_t *paddr, in
 	pte = ULONG(machdep->ptbl + PAGEOFFSET(ptep));
 	if (verbose)
 		fprintf(fp, "   PTE: %lx => %lx\n", (ulong)ptep, pte);
-	if (!(pte & (_PAGE_PRESENT))) {
+
+	if (!(pte & (_PAGE_PRESENT | _PAGE_PROTNONE))) {
 		*paddr = pte;
 
 		if (pte && verbose) {