[Crash-utility] crash version 4.0-3.15 is available

[Itsuro ODA]

Hi Dave,

> - Introduced support for xendumps of para-virtualized ia64 kernels.
>   It should be noted that currently the ia64 Xen kernel does not
>   lay down a switch_stack for the panic task, so only raw "bt -t"
>   backtraces can be done on the panic task.  (anderson at redhat.com)

page_index may contain INVALID_MFN (0xffffffffffffffffUL).
I think it is better to check it.
Here is a patch for this.

---
--- crash-4.0-3.15-org/xendump.h	2006-12-21 09:57:29.000000000 +0900
+++ crash-4.0-3.15/xendump.h	2006-12-21 14:37:35.000000000 +0900
@@ -113,3 +113,8 @@
     uint32_t hypercall_imm; /* Break imm for Xen hypercalls.  */
 /* #endif */
 } xen_domctl_arch_setup_t;
+
+#ifdef IA64
+#define INVALID_MFN (0xffffffffffffffffUL)
+#endif
+
--- crash-4.0-3.15-org/xendump.c	2006-12-21 09:57:29.000000000 +0900
+++ crash-4.0-3.15/xendump.c	2006-12-21 14:42:48.000000000 +0900
@@ -31,6 +31,7 @@
 
 static void xc_core_p2m_create(void);
 static ulong xc_core_pfn_to_page_index(ulong);
+static int check_mfn_is_valid(ulong);
 
 /*
  *  Determine whether a file is a xendump creation, and if TRUE,
@@ -1362,7 +1363,7 @@
 	off_t offset;
 
 	if (xd->flags & XC_CORE_NO_P2MM)
-		return pfn;
+		return check_mfn_is_valid(pfn) ? pfn : PFN_NOT_FOUND;
 
 	idx = pfn/PFNS_PER_PAGE;
 
@@ -1405,6 +1406,34 @@
 	return mfn_idx;
 }
 
+static int
+check_mfn_is_valid(ulong idx)
+{
+        ulong mfn;
+
+	if (idx >= xd->xc_core.header.xch_nr_pages)
+		return FALSE;
+
+        if (lseek(xd->xfd,
+	    (off_t)xd->xc_core.header.xch_index_offset + idx * sizeof(ulong),
+            SEEK_SET) == -1) {
+                error(INFO, "cannot lseek to page index\n");
+                return FALSE;
+        }
+
+	if (read(xd->xfd, &mfn, sizeof(ulong)) != sizeof(ulong)) {
+		error(INFO, "cannot read index page %d\n", idx);
+		return FALSE;
+	}
+
+	if (mfn == INVALID_MFN) {
+		error(INFO, "idx: %lx indicates INVALID_MFN\n", idx);
+		return FALSE;
+	} else {
+		return TRUE;
+	}
+}
+
 /*
  *  Store the panic task's stack hooks from where it was found
  *  in get_active_set_panic_task().
---

Thanks.
-- 
Itsuro ODA <oda at valinux.co.jp>