bug in sbrk

test malloc

proc.c

@@ -151,10 +151,9 @@ growproc(int n)
   oldmem = cp->mem;
   cp->mem = newmem;
   kfree(oldmem, cp->sz);
+  cprintf("growproc: added %d bytes to %d bytes\n", n, cp->sz);
   cp->sz += n;
-  cprintf("growproc: added %d bytes starting at address 0x%x\n", n, 
+  return cp->sz - n;
-	  newmem + cp->sz - n);
-  return newmem + cp->sz - n;
 }
 
 // Per-CPU process scheduler. 

umalloc.c

@@ -25,7 +25,9 @@ void
 free(void *ap)
 {
   Header *bp, *p;
-  
+
+  printf(1, "free\n");
+
   bp = (Header *) ap - 1;
   for (p = freep; !(bp > p && bp < p->s.ptr); p = p->s.ptr)
     if (p >= p->s.ptr && (bp > p || bp < p->s.ptr))
@@ -51,6 +53,7 @@ morecore(uint nu)
   
   if (nu < PAGE)
     nu = PAGE;
+  printf(1, "call sbrk\n");
   cp = sbrk(nu * sizeof(Header));
   if (cp == (char *) -1)
     return 0;
@@ -66,6 +69,8 @@ malloc(uint nbytes)
   Header *p, *prevp;
   uint nunits;
 
+  printf(1, "malloc %d\n", nbytes);
+
   nunits = (nbytes + sizeof(Header) - 1)/sizeof(Header) + 1;
   if ((prevp = freep) == 0) {
     base.s.ptr = freep = prevp = &base;
@@ -81,6 +86,7 @@ malloc(uint nbytes)
 	p->s.size = nunits;
       }
       freep = prevp;
+      printf(1, "malloc returns: %d\n", (int) (p+1));
       return (void *) (p + 1);
     }
     if (p == freep) 

user.h

@@ -30,5 +30,5 @@ void printf(int fd, char *fmt, ...);
 char *gets(char *, int max);
 unsigned int strlen(char *);
 void * memset(void *dst, int c, unsigned int n);
-void *mallic(uint);
+void *malloc(uint);
 void free(void *);

usertests.c

@@ -117,14 +117,50 @@ exitwait(void)
   puts("exitwait ok\n");
 }
 
+void
+mem(void)
+{
+  void *m = malloc(4096);
+  void *m1, *m2;
+
+  free(m + 3*1024);
+  free(m + 2*1024);
+  free(m + 1024);
+  free(m);
+  m1 = malloc(4096);
+  if (m1 != m) {
+    puts("didn't coalesce\n");
+    exit();
+  }
+  free(m1);
+  
+  m1 = 0;
+  while ((m2 = malloc(1024)) != 0) {
+    *(char **) m2 = m1;
+    m1 = m2;
+  }
+  while (m1) {
+    m2 = *(char **)m1;
+    free(m1);
+    m1 = m2;
+  }
+  m1 = malloc(1024*20);
+  if (m1 == 0) {
+    puts("couldn't allocate mem?!!\n");
+    exit();
+  }
+  free(m1);
+}
+
 int
 main(int argc, char *argv[])
 {
   puts("usertests starting\n");
 
-  pipe1();
+  // pipe1();
-  preempt();
+  // preempt();
-  exitwait();
+  // exitwait();
+  mem();
 
   puts("usertests finished\n");
   exit();