4 files changed, 37 insertions, 0 deletions
diff --git a/src/cmd/cover/cover_test.go b/src/cmd/cover/cover_test.go
index a1149e9e6e..a19e0d0924 100644
--- a/src/cmd/cover/cover_test.go
+++ b/src/cmd/cover/cover_test.go
@@ -638,3 +638,12 @@ func main() {
 		t.Errorf("unexpected success; want failure due to newline in file path")
 	}
 }
+
+func TestAlignment(t *testing.T) {
+	// Test that cover data structures are aligned appropriately. See issue 58936.
+	testenv.MustHaveGoRun(t)
+	t.Parallel()
+
+	cmd := testenv.Command(t, testenv.GoToolPath(t), "test", "-cover", filepath.Join(testdata, "align.go"), filepath.Join(testdata, "align_test.go"))
+	run(cmd, t)
+}
diff --git a/src/cmd/cover/testdata/align.go b/src/cmd/cover/testdata/align.go
new file mode 100644
index 0000000000..2e8a45345d
--- /dev/null
+++ b/src/cmd/cover/testdata/align.go
@@ -0,0 +1,11 @@
+// Copyright 2026 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+var badSlice [8265]byte
+
+func init() {
+	badSlice[0] = 4
+}
diff --git a/src/cmd/cover/testdata/align_test.go b/src/cmd/cover/testdata/align_test.go
new file mode 100644
index 0000000000..e908c5a1cb
--- /dev/null
+++ b/src/cmd/cover/testdata/align_test.go
@@ -0,0 +1,10 @@
+// Copyright 2026 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package p
+
+import "testing"
+
+func TestFoo(t *testing.T) {
+}
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 683df3bb67..a045ff5eea 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -2022,6 +2022,13 @@ func (state *dodataState) allocateDataSections(ctxt *Link) {
 	ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.covctrs", 0), sect)
 	ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.ecovctrs", 0), sect)
 
+	// If we started this blob at an odd alignment, then covctrs will
+	// not be correctly aligned. Each individual entry is aligned properly,
+	// but the start marker may be before any padding inserted to enforce
+	// that alignment. Fix that here. See issue 58936.
+	covCounterDataStartOff += covCounterDataLen % 4
+	covCounterDataLen -= covCounterDataLen % 4
+
 	// Coverage instrumentation counters for libfuzzer.
 	if len(state.data[sym.SLIBFUZZER_8BIT_COUNTER]) > 0 {
 		sect := state.allocateNamedSectionAndAssignSyms(&Segdata, ".go.fuzzcntrs", sym.SLIBFUZZER_8BIT_COUNTER, sym.Sxxx, 06)