net, internal/poll: reset value before adding in minor kernel version

Fixes #42733

Change-Id: I5446aeb5de13cd70212755fb12c9bc484f343c74
Reviewed-on: https://go-review.googlesource.com/c/go/+/271846
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/src/internal/poll/copy_file_range_linux.go b/src/internal/poll/copy_file_range_linux.go
index 1635bb1..fc34aef 100644
--- a/src/internal/poll/copy_file_range_linux.go
+++ b/src/internal/poll/copy_file_range_linux.go
@@ -35,6 +35,7 @@
 			if vi >= len(values) {
 				break
 			}
+			value = 0
 		}
 	}
 	switch vi {
diff --git a/src/net/sock_linux.go b/src/net/sock_linux.go
index 4d91001..9f62ed3 100644
--- a/src/net/sock_linux.go
+++ b/src/net/sock_linux.go
@@ -27,6 +27,7 @@
 			if vi >= len(values) {
 				break
 			}
+			value = 0
 		}
 	}
 	switch vi {