kmemcheck: add the kmemcheck core

General description: kmemcheck is a patch to the linux kernel that
detects use of uninitialized memory. It does this by trapping every
read and write to memory that was allocated dynamically (e.g. using
kmalloc()). If a memory address is read that has not previously been
written to, a message is printed to the kernel log.

Thanks to Andi Kleen for the set_memory_4k() solution.

Andrew Morton suggested documenting the shadow member of struct page.

Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

[export kmemcheck_mark_initialized]
[build fix for setup_max_cpus]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>

1 files changed, 12 insertions, 0 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ce664f98e3fb..9ef80bba3509 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -27,6 +27,7 @@
 #include <linux/security.h>
 #include <linux/ctype.h>
 #include <linux/utsname.h>
+#include <linux/kmemcheck.h>
 #include <linux/smp_lock.h>
 #include <linux/fs.h>
 #include <linux/init.h>
@@ -959,6 +960,17 @@ static struct ctl_table kern_table[] = {
                 .proc_handler   = &proc_dointvec,
         },
 #endif
+#ifdef CONFIG_KMEMCHECK
+        {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "kmemcheck",
+                .data           = &kmemcheck_enabled,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
+#endif
+
 /*
  * NOTE: do not add new entries to this table unless you have read
  * Documentation/sysctl/ctl_unnumbered.txt