Kernel: Add kmalloc scan

This will scan for possible overflows in the program. It is a somewhat
expensive operation but really useful for debugging.

4 files changed, 15 insertions, 3 deletions

diff --git a/kernel/drivers/pit.c b/kernel/drivers/pit.c
index b875449..8210aa7 100644
--- a/kernel/drivers/pit.c
+++ b/kernel/drivers/pit.c
@@ -1,5 +1,6 @@
 #include "pit.h"
 #include <arch/i386/tsc.h>
+#include <kmalloc.h>
 #include <random.h>
 
 #define PIT_IO_CHANNEL_0 0x40
@@ -47,6 +48,7 @@ u64 last_tsc = 0;
 extern u64 timer_current_uptime;
 extern int is_switching_tasks;
 void int_clock(reg_t *regs) {
+  kmalloc_scan();
   u64 current_tsc = tsc_get();
   timer_current_uptime = tsc_calculate_ms(current_tsc);
   random_add_entropy_fast((u8 *)&current_tsc, sizeof(current_tsc));
diff --git a/kernel/kmalloc.c b/kernel/kmalloc.c
index 939589d..86c4eda 100644
--- a/kernel/kmalloc.c
+++ b/kernel/kmalloc.c
@@ -100,7 +100,7 @@ int add_heap_memory(size_t min_desired) {
   return 1;
 }
 
-MallocHeader *next_header(MallocHeader *a) {
+static MallocHeader *next_header(MallocHeader *a) {
   assert(a->magic == 0xdde51ab9410268b1);
   if (a->n) {
     if (a->n->magic != 0xdde51ab9410268b1) {
@@ -113,7 +113,16 @@ MallocHeader *next_header(MallocHeader *a) {
   return NULL;
 }
 
-MallocHeader *next_close_header(MallocHeader *a) {
+void kmalloc_scan(void) {
+  if (!head) {
+    return;
+  }
+  MallocHeader *p = head;
+  for (; (p = next_header(p));)
+    ;
+}
+
+static MallocHeader *next_close_header(MallocHeader *a) {
   if (!a) {
     kprintf("next close header fail\n");
     for (;;)
diff --git a/kernel/kmalloc.h b/kernel/kmalloc.h
index 9c03a19..74e4d81 100644
--- a/kernel/kmalloc.h
+++ b/kernel/kmalloc.h
@@ -8,6 +8,8 @@ void kmalloc_align_free(void *p, size_t s);
 
 void kmalloc_allocate_heap(void);
 
+void kmalloc_scan(void);
+
 void *kmalloc(size_t s);
 void *krealloc(void *ptr, size_t size);
 void *kreallocarray(void *ptr, size_t nmemb, size_t size);
diff --git a/kernel/sched/scheduler.c b/kernel/sched/scheduler.c
index d04b6e7..9032ac5 100644
--- a/kernel/sched/scheduler.c
+++ b/kernel/sched/scheduler.c
@@ -442,7 +442,6 @@ process_t *next_task(process_t *s) {
     }
     if (s == c) {
       ms_time = timer_get_uptime();
-      // wait_for_interrupt();
     }
     if (c->sleep_until > ms_time) {
       continue;