Merge pull request #4927 from cyphar/1.4-cpuset-fill

[1.4] libct: switch to (*CPUSet).Fill

Author: rata

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased 1.4.z]
 
+### Fixed
+ * Switched to `(*CPUSet).Fill` rather than our hacky optimisation when
+   resetting the CPU affinity of runc. (#4926, #4927)
+
 ## [1.4.0-rc.2] - 2025-10-10
 
 > 私の役目は信じるかどうかではない。行うかどうかだ。

go.mod

@@ -23,7 +23,7 @@ require (
 	github.com/vishvananda/netlink v1.3.1
 	github.com/vishvananda/netns v0.0.5
 	golang.org/x/net v0.43.0
-	golang.org/x/sys v0.35.0
+	golang.org/x/sys v0.37.0
 	google.golang.org/protobuf v1.36.8
 )
 

go.sum

@@ -84,8 +84,8 @@ golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
-golang.org/x/sys v0.35.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
+golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
 google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

libcontainer/process_linux.go

@@ -185,16 +185,8 @@ func tryResetCPUAffinity(pid int) {
 	//
 	// So we can just pass a very large array of set cpumask bits and the
 	// kernel will silently convert that to the correct value very cheaply.
-
-	// Ideally, we would just set the array to 0xFF...FF. Unfortunately, the
-	// size depends on the architecture. It is also a private newtype, so we
-	// can't use (^0) or generics since those require us to be able to name the
-	// type. However, we can just underflow the zero value instead.
-	// TODO: Once <https://golang.org/cl/698015> is merged, switch to that.
-	cpuset := unix.CPUSet{}
-	for i := range cpuset {
-		cpuset[i]-- // underflow to 0xFF..FF
-	}
+	var cpuset unix.CPUSet
+	cpuset.Fill() // set all bits
 	if err := unix.SchedSetaffinity(pid, &cpuset); err != nil {
 		logrus.WithError(
 			os.NewSyscallError("sched_setaffinity", err),