1 files changed, 4 insertions, 37 deletions

diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index 0f1a5c1c55..1bd7e87b2e 100644
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -320,7 +320,7 @@ func stackcache_clear(c *mcache) {
 // resources and must not split the stack.
 //
 //go:systemstack
-func stackalloc(n uint32) (stack, []stkbar) {
+func stackalloc(n uint32) stack {
 	// 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).
@@ -335,21 +335,12 @@ func stackalloc(n uint32) (stack, []stkbar) {
 		print("stackalloc ", n, "\n")
 	}
 
-	// Compute the size of stack barrier array.
-	maxstkbar := gcMaxStackBarriers(int(n))
-	nstkbar := unsafe.Sizeof(stkbar{}) * uintptr(maxstkbar)
-	var stkbarSlice slice
-
 	if debug.efence != 0 || stackFromSystem != 0 {
 		v := sysAlloc(round(uintptr(n), _PageSize), &memstats.stacks_sys)
 		if v == nil {
 			throw("out of memory (stackalloc)")
 		}
-		top := uintptr(n) - nstkbar
-		if maxstkbar != 0 {
-			stkbarSlice = slice{add(v, top), 0, maxstkbar}
-		}
-		return stack{uintptr(v), uintptr(v) + top}, *(*[]stkbar)(unsafe.Pointer(&stkbarSlice))
+		return stack{uintptr(v), uintptr(v) + uintptr(n)}
 	}
 
 	// Small stacks are allocated with a fixed-size free-list allocator.
@@ -415,11 +406,7 @@ func stackalloc(n uint32) (stack, []stkbar) {
 	if stackDebug >= 1 {
 		print("  allocated ", v, "\n")
 	}
-	top := uintptr(n) - nstkbar
-	if maxstkbar != 0 {
-		stkbarSlice = slice{add(v, top), 0, maxstkbar}
-	}
-	return stack{uintptr(v), uintptr(v) + top}, *(*[]stkbar)(unsafe.Pointer(&stkbarSlice))
+	return stack{uintptr(v), uintptr(v) + uintptr(n)}
 }
 
 // stackfree frees an n byte stack allocation at stk.
@@ -774,12 +761,6 @@ func adjustsudogs(gp *g, adjinfo *adjustinfo) {
 	}
 }
 
-func adjuststkbar(gp *g, adjinfo *adjustinfo) {
-	for i := int(gp.stkbarPos); i < len(gp.stkbar); i++ {
-		adjustpointer(adjinfo, unsafe.Pointer(&gp.stkbar[i].savedLRPtr))
-	}
-}
-
 func fillstack(stk stack, b byte) {
 	for p := stk.lo; p < stk.hi; p++ {
 		*(*byte)(unsafe.Pointer(p)) = b
@@ -866,7 +847,7 @@ func copystack(gp *g, newsize uintptr, sync bool) {
 	used := old.hi - gp.sched.sp
 
 	// allocate new stack
-	new, newstkbar := stackalloc(uint32(newsize))
+	new := stackalloc(uint32(newsize))
 	if stackPoisonCopy != 0 {
 		fillstack(new, 0xfd)
 	}
@@ -900,39 +881,27 @@ func copystack(gp *g, newsize uintptr, sync bool) {
 	// Copy the stack (or the rest of it) to the new location
 	memmove(unsafe.Pointer(new.hi-ncopy), unsafe.Pointer(old.hi-ncopy), ncopy)
 
-	// Disallow sigprof scans of this stack and block if there's
-	// one in progress.
-	gcLockStackBarriers(gp)
-
 	// Adjust remaining structures that have pointers into stacks.
 	// We have to do most of these before we traceback the new
 	// stack because gentraceback uses them.
 	adjustctxt(gp, &adjinfo)
 	adjustdefers(gp, &adjinfo)
 	adjustpanics(gp, &adjinfo)
-	adjuststkbar(gp, &adjinfo)
 	if adjinfo.sghi != 0 {
 		adjinfo.sghi += adjinfo.delta
 	}
 
-	// copy old stack barriers to new stack barrier array
-	newstkbar = newstkbar[:len(gp.stkbar)]
-	copy(newstkbar, gp.stkbar)
-
 	// Swap out old stack for new one
 	gp.stack = new
 	gp.stackguard0 = new.lo + _StackGuard // NOTE: might clobber a preempt request
 	gp.sched.sp = new.hi - used
 	oldsize := gp.stackAlloc
 	gp.stackAlloc = newsize
-	gp.stkbar = newstkbar
 	gp.stktopsp += adjinfo.delta
 
 	// Adjust pointers in the new stack.
 	gentraceback(^uintptr(0), ^uintptr(0), 0, gp, 0, nil, 0x7fffffff, adjustframe, noescape(unsafe.Pointer(&adjinfo)), 0)
 
-	gcUnlockStackBarriers(gp)
-
 	// free old stack
 	if stackPoisonCopy != 0 {
 		fillstack(old, 0xfc)
@@ -1132,8 +1101,6 @@ func shrinkstack(gp *g) {
 			stackfree(gp.stack, gp.stackAlloc)
 			gp.stack.lo = 0
 			gp.stack.hi = 0
-			gp.stkbar = nil
-			gp.stkbarPos = 0
 		}
 		return
 	}