Imported Upstream version 2011.03.07.1upstream/2011.03.07.1

1 files changed, 15 insertions, 2 deletions

diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
index 70b85d68d..41060682e 100644
--- a/src/pkg/runtime/malloc.goc
+++ b/src/pkg/runtime/malloc.goc
@@ -8,6 +8,7 @@
 
 package runtime
 #include "runtime.h"
+#include "stack.h"
 #include "malloc.h"
 #include "defs.h"
 #include "type.h"
@@ -146,6 +147,9 @@ runtime·free(void *v)
 		// Large object.
 		size = s->npages<<PageShift;
 		*(uintptr*)(s->start<<PageShift) = 1;	// 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.
+		runtime·markfreed(v, size);
 		runtime·unmarkspan(v, 1<<PageShift);
 		runtime·MHeap_Free(&runtime·mheap, s, 1);
 	} else {
@@ -154,10 +158,13 @@ runtime·free(void *v)
 		size = runtime·class_to_size[sizeclass];
 		if(size > sizeof(uintptr))
 			((uintptr*)v)[1] = 1;	// mark as "needs to be zeroed"
+		// Must mark v freed before calling MCache_Free:
+		// it might coalesce v and other blocks into a bigger span
+		// and change the bitmap further.
+		runtime·markfreed(v, size);
 		mstats.by_size[sizeclass].nfree++;
 		runtime·MCache_Free(c, v, sizeclass, size);
 	}
-	runtime·markfreed(v, size);
 	mstats.alloc -= size;
 	if(prof)
 		runtime·MProf_Free(v, size);
@@ -379,7 +386,7 @@ static struct {
 } stacks;
 
 enum {
-	FixedStack = StackBig + StackExtra
+	FixedStack = StackMin,
 };
 
 void*
@@ -387,6 +394,12 @@ runtime·stackalloc(uint32 n)
 {
 	void *v;
 
+	// Stackalloc must be called on scheduler stack, so that we
+	// never try to grow the stack during the code that stackalloc runs.
+	// Doing so would cause a deadlock (issue 1547).
+	if(g != m->g0)
+		runtime·throw("stackalloc not on scheduler stack");
+
 	if(m->mallocing || m->gcing || n == FixedStack) {
 		runtime·lock(&stacks);
 		if(stacks.size == 0)