runtime: deallocate specials before deallocating the underlying object.

R=dvyukov
CC=golang-codereviews
https://golang.org/cl/48840043

diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index 81cda75dfd187ebfe0395dab933a59c39cbd84a6..9a25029586d6ed127bd64412632db69feab3079e 100644 (file)
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -180,16 +180,18 @@ runtime·free(void *v)
                runtime·printf("free %p: not an allocated block\n", v);
                runtime·throw("free runtime·mlookup");
        }
+       size = s->elemsize;
+       sizeclass = s->sizeclass;
 
        if(raceenabled)
                runtime·racefree(v);
 
-       // Find size class for v.
-       sizeclass = s->sizeclass;
+       if(s->specials != nil)
+               runtime·freeallspecials(s, v, size);
+
        c = m->mcache;
        if(sizeclass == 0) {
                // Large object.
-               size = s->npages<<PageShift;
                *(uintptr*)(s->start<<PageShift) = (uintptr)0xfeedfeedfeedfeedll;       // mark as "needs to be zeroed"
                // Must mark v freed before calling unmarkspan and MHeap_Free:
                // they might coalesce v into other spans and change the bitmap further.
@@ -203,7 +205,6 @@ runtime·free(void *v)
                c->local_largefree += size;
        } else {
                // Small object.
-               size = runtime·class_to_size[sizeclass];
                if(size > sizeof(uintptr))
                        ((uintptr*)v)[1] = (uintptr)0xfeedfeedfeedfeedll;       // mark as "needs to be zeroed"
                // Must mark v freed before calling MCache_Free:
@@ -213,8 +214,6 @@ runtime·free(void *v)
                c->local_nsmallfree[sizeclass]++;
                runtime·MCache_Free(c, v, sizeclass, size);
        }
-       if(s->specials != nil)
-               runtime·freeallspecials(s, v, size);
        m->mallocing = 0;
 }