[PATCH] taint on bad_page

Hugh and I both thought this would be generally useful.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/kernel.h

@@ -152,6 +152,7 @@ extern enum system_states {
 #define TAINT_UNSAFE_SMP		(1<<2)
 #define TAINT_FORCED_RMMOD		(1<<3)
 #define TAINT_MACHINE_CHECK		(1<<4)
+#define TAINT_BAD_PAGE			(1<<5)
 
 extern void dump_stack(void);
 

kernel/panic.c

@@ -112,6 +112,7 @@ EXPORT_SYMBOL(panic);
  *  'S' - SMP with CPUs not designed for SMP.
  *  'R' - User forced a module unload.
  *  'M' - Machine had a machine check experience.
+ *  'B' - System has hit bad_page.
  *
  *	The string is overwritten by the next call to print_taint().
  */
@@ -120,12 +121,13 @@ const char *print_tainted(void)
 {
 	static char buf[20];
 	if (tainted) {
-		snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c",
+		snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c",
 			tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 			tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 			tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
 			tainted & TAINT_FORCED_RMMOD ? 'R' : ' ',
- 			tainted & TAINT_MACHINE_CHECK ? 'M' : ' ');
+ 			tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
+			tainted & TAINT_BAD_PAGE ? 'B' : ' ');
 	}
 	else
 		snprintf(buf, sizeof(buf), "Not tainted");

mm/page_alloc.c

@@ -94,6 +94,7 @@ static void bad_page(const char *function, struct page *page)
 	set_page_count(page, 0);
 	reset_page_mapcount(page);
 	page->mapping = NULL;
+	tainted |= TAINT_BAD_PAGE;
 }
 
 #ifndef CONFIG_HUGETLB_PAGE