diff --git a/CHANGELOG.md b/CHANGELOG.md
index fb035a12c..6f029caf1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 2.25.1 / 2021-03-14
+
+* [BUGFIX] Fix a crash in `promtool` when a subquery with default resolution is used. #8569
+* [BUGFIX] Fix a bug that could return duplicate datapoints in queries. #8591
+* [BUGFIX] Fix crashes with arm64 when compiled with go1.16. #8593
+
 ## 2.25.0 / 2021-02-17
 
 This release includes a new `--enable-feature=` flag that enables
diff --git a/VERSION b/VERSION
index 5c18f9195..d6af7e332 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.25.0
+2.25.1
diff --git a/cmd/promtool/testdata/rules.yml b/cmd/promtool/testdata/rules.yml
index 7eff7f8f0..db33d343f 100644
--- a/cmd/promtool/testdata/rules.yml
+++ b/cmd/promtool/testdata/rules.yml
@@ -20,3 +20,7 @@ groups:
       # A recording rule that doesn't depend on input series.
       - record: fixed_data
         expr: 1
+
+      # Subquery with default resolution test.
+      - record: suquery_interval_test
+        expr: count_over_time(up[5m:])
diff --git a/cmd/promtool/unittest.go b/cmd/promtool/unittest.go
index 64107f171..ea55ac04c 100644
--- a/cmd/promtool/unittest.go
+++ b/cmd/promtool/unittest.go
@@ -157,6 +157,7 @@ func (tg *testGroup) test(evalInterval time.Duration, groupOrderMap map[string]i
 		return []error{err}
 	}
 	defer suite.Close()
+	suite.SubqueryInterval = evalInterval
 
 	// Load the rule files.
 	opts := &rules.ManagerOptions{
diff --git a/docs/configuration/unit_testing_rules.md b/docs/configuration/unit_testing_rules.md
index 3043b2edf..644b35a17 100644
--- a/docs/configuration/unit_testing_rules.md
+++ b/docs/configuration/unit_testing_rules.md
@@ -22,8 +22,7 @@ You can use `promtool` to test your rules.
 rule_files:
   [ - <file_name> ]
 
-# optional, default = 1m
-evaluation_interval: <duration>
+[ evaluation_interval: <duration> | default = 1m ]
 
 # The order in which group names are listed below will be the order of evaluation of
 # rule groups (at a given evaluation time). The order is guaranteed only for the groups mentioned below.
diff --git a/go.mod b/go.mod
index 56807a7ba..d8cd3a0cb 100644
--- a/go.mod
+++ b/go.mod
@@ -25,7 +25,7 @@ require (
 	github.com/go-openapi/strfmt v0.20.0
 	github.com/go-openapi/validate v0.20.2 // indirect
 	github.com/gogo/protobuf v1.3.2
-	github.com/golang/snappy v0.0.2
+	github.com/golang/snappy v0.0.3
 	github.com/google/pprof v0.0.0-20210208152844-1612e9be7af6
 	github.com/gophercloud/gophercloud v0.15.0
 	github.com/grpc-ecosystem/grpc-gateway v1.16.0
diff --git a/go.sum b/go.sum
index 5ba7e46a2..394900e1f 100644
--- a/go.sum
+++ b/go.sum
@@ -390,8 +390,8 @@ github.com/golang/protobuf v1.4.3 h1:JjCZWpVbqXDqFVmTfYWEVTMIYrL/NPdPSCHPJ0T/raM
 github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/snappy v0.0.0-20180518054509-2e65f85255db/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/golang/snappy v0.0.1/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
-github.com/golang/snappy v0.0.2 h1:aeE13tS0IiQgFjYdoL8qN3K1N2bXXtI6Vi51/y7BpMw=
-github.com/golang/snappy v0.0.2/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/golang/snappy v0.0.3 h1:fHPg5GQYlCeLIPB9BZqMVR5nR9A+IM5zcgeTdjMYmLA=
+github.com/golang/snappy v0.0.3/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0 h1:0udJVsspx3VBr5FwtLhQQtuAsVc79tTq0ocGIPAU6qo=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
diff --git a/promql/test.go b/promql/test.go
index 77e133eed..9775e68f5 100644
--- a/promql/test.go
+++ b/promql/test.go
@@ -657,7 +657,8 @@ type LazyLoader struct {
 
 	loadCmd *loadCmd
 
-	storage storage.Storage
+	storage          storage.Storage
+	SubqueryInterval time.Duration
 
 	queryEngine *Engine
 	context     context.Context
@@ -710,11 +711,12 @@ func (ll *LazyLoader) clear() {
 	ll.storage = teststorage.New(ll)
 
 	opts := EngineOpts{
-		Logger:           nil,
-		Reg:              nil,
-		MaxSamples:       10000,
-		Timeout:          100 * time.Second,
-		EnableAtModifier: true,
+		Logger:                   nil,
+		Reg:                      nil,
+		MaxSamples:               10000,
+		Timeout:                  100 * time.Second,
+		NoStepSubqueryIntervalFn: func(int64) int64 { return durationMilliseconds(ll.SubqueryInterval) },
+		EnableAtModifier:         true,
 	}
 
 	ll.queryEngine = NewEngine(opts)
diff --git a/storage/merge.go b/storage/merge.go
index c57a24c76..fca052ca1 100644
--- a/storage/merge.go
+++ b/storage/merge.go
@@ -467,6 +467,7 @@ func (c *chainSampleIterator) Seek(t int64) bool {
 	}
 	if len(c.h) > 0 {
 		c.curr = heap.Pop(&c.h).(chunkenc.Iterator)
+		c.lastt, _ = c.curr.At()
 		return true
 	}
 	c.curr = nil
diff --git a/storage/merge_test.go b/storage/merge_test.go
index 415b7fb60..2ed68879a 100644
--- a/storage/merge_test.go
+++ b/storage/merge_test.go
@@ -647,6 +647,14 @@ func TestChainSampleIteratorSeek(t *testing.T) {
 			seek:     2,
 			expected: []tsdbutil.Sample{sample{2, 2}, sample{3, 3}, sample{4, 4}, sample{5, 5}},
 		},
+		{
+			input: []chunkenc.Iterator{
+				NewListSeriesIterator(samples{sample{0, 0}, sample{2, 2}, sample{3, 3}}),
+				NewListSeriesIterator(samples{sample{0, 0}, sample{1, 1}, sample{2, 2}}),
+			},
+			seek:     0,
+			expected: []tsdbutil.Sample{sample{0, 0}, sample{1, 1}, sample{2, 2}, sample{3, 3}},
+		},
 	} {
 		merged := newChainSampleIterator(tc.input)
 		actual := []tsdbutil.Sample{}