Pids-limit should only be set if the user set it

Currently we are sending over pids-limits from the user even if they never modified the defaults. The pids limit should be set at the server side unless modified by the user. This issue has led to failures on systems that were running with cgroups V1. Signed-off-by: Daniel J Walsh <[email protected]>
containers · Jul 10, 2020 · 677ad10 · 677ad10
1 parent 2ac8c69
commit 677ad10
Show file tree

Hide file tree

Showing 6 changed files with 43 additions and 28 deletions.
diff --git a/cmd/podman/common/create.go b/cmd/podman/common/create.go
@@ -330,8 +330,7 @@ func GetCreateFlags(cf *ContainerCLIOpts) *pflag.FlagSet {
 		"pid", "",
 		"PID namespace to use",
 	)
-	createFlags.Int64Var(
-		&cf.PIDsLimit,
+	createFlags.Int64(
 		"pids-limit", containerConfig.PidsLimit(),
 		"Tune container pids limit (set 0 for unlimited, -1 for server defaults)",
 	)

diff --git a/cmd/podman/common/create_opts.go b/cmd/podman/common/create_opts.go
@@ -66,7 +66,7 @@ type ContainerCLIOpts struct {
 	OverrideArch      string
 	OverrideOS        string
 	PID               string
-	PIDsLimit         int64
+	PIDsLimit         *int64
 	Pod               string
 	PodIDFile         string
 	PreserveFDs       uint

diff --git a/cmd/podman/common/specgen.go b/cmd/podman/common/specgen.go
@@ -7,14 +7,12 @@ import (
 	"strings"
 	"time"
 
-	"github.com/containers/common/pkg/config"
 	"github.com/containers/image/v5/manifest"
 	"github.com/containers/libpod/v2/cmd/podman/parse"
 	"github.com/containers/libpod/v2/libpod/define"
 	ann "github.com/containers/libpod/v2/pkg/annotations"
 	envLib "github.com/containers/libpod/v2/pkg/env"
 	ns "github.com/containers/libpod/v2/pkg/namespaces"
-	"github.com/containers/libpod/v2/pkg/rootless"
 	"github.com/containers/libpod/v2/pkg/specgen"
 	systemdGen "github.com/containers/libpod/v2/pkg/systemd/generate"
 	"github.com/containers/libpod/v2/pkg/util"
@@ -127,25 +125,6 @@ func getIOLimits(s *specgen.SpecGenerator, c *ContainerCLIOpts) (*specs.LinuxBlo
 	return io, nil
 }
 
-func getPidsLimits(c *ContainerCLIOpts) *specs.LinuxPids {
-	pids := &specs.LinuxPids{}
-	if c.CGroupsMode == "disabled" && c.PIDsLimit != 0 {
-		return nil
-	}
-	if c.PIDsLimit < 0 {
-		if rootless.IsRootless() && containerConfig.Engine.CgroupManager != config.SystemdCgroupsManager {
-			return nil
-		}
-		pids.Limit = containerConfig.PidsLimit()
-		return pids
-	}
-	if c.PIDsLimit > 0 {
-		pids.Limit = c.PIDsLimit
-		return pids
-	}
-	return nil
-}
-
 func getMemoryLimits(s *specgen.SpecGenerator, c *ContainerCLIOpts) (*specs.LinuxMemory, error) {
 	var err error
 	memory := &specs.LinuxMemory{}
@@ -457,7 +436,13 @@ func FillOutSpecGen(s *specgen.SpecGenerator, c *ContainerCLIOpts, args []string
 	if err != nil {
 		return err
 	}
-	s.ResourceLimits.Pids = getPidsLimits(c)
+	if c.PIDsLimit != nil {
+		pids := specs.LinuxPids{
+			Limit: *c.PIDsLimit,
+		}
+
+		s.ResourceLimits.Pids = &pids
+	}
 	s.ResourceLimits.CPU = getCPULimits(c)
 	if s.ResourceLimits.CPU == nil && s.ResourceLimits.Pids == nil && s.ResourceLimits.BlockIO == nil && s.ResourceLimits.Memory == nil {
 		s.ResourceLimits = nil

diff --git a/cmd/podman/containers/create.go b/cmd/podman/containers/create.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/containers/common/pkg/config"
@@ -195,13 +196,18 @@ func createInit(c *cobra.Command) error {
 	cliVals.UTS = c.Flag("uts").Value.String()
 	cliVals.PID = c.Flag("pid").Value.String()
 	cliVals.CGroupsNS = c.Flag("cgroupns").Value.String()
-	if !c.Flag("pids-limit").Changed {
-		cliVals.PIDsLimit = -1
-	}
 	if c.Flag("entrypoint").Changed {
 		val := c.Flag("entrypoint").Value.String()
 		cliVals.Entrypoint = &val
 	}
+	if c.Flags().Changed("pids-limit") {
+		val := c.Flag("pids-limit").Value.String()
+		pidsLimit, err := strconv.ParseInt(val, 10, 32)
+		if err != nil {
+			return err
+		}
+		cliVals.PIDsLimit = &pidsLimit
+	}
 	if c.Flags().Changed("env") {
 		env, err := c.Flags().GetStringArray("env")
 		if err != nil {

diff --git a/pkg/specgen/generate/container.go b/pkg/specgen/generate/container.go
@@ -10,6 +10,7 @@ import (
 	envLib "github.com/containers/libpod/v2/pkg/env"
 	"github.com/containers/libpod/v2/pkg/signal"
 	"github.com/containers/libpod/v2/pkg/specgen"
+	spec "github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/pkg/errors"
 	"golang.org/x/sys/unix"
 )
@@ -169,6 +170,21 @@ func CompleteSpec(ctx context.Context, r *libpod.Runtime, s *specgen.SpecGenerat
 		}
 	}
 
+	// If caller did not specify Pids Limits load default
+	if s.ResourceLimits == nil || s.ResourceLimits.Pids == nil {
+		if s.CgroupsMode != "disabled" {
+			limit := rtc.PidsLimit()
+			if limit != 0 {
+				if s.ResourceLimits == nil {
+					s.ResourceLimits = &spec.LinuxResources{}
+				}
+				s.ResourceLimits.Pids = &spec.LinuxPids{
+					Limit: limit,
+				}
+			}
+		}
+	}
+
 	return verifyContainerResources(s)
 }
 

diff --git a/test/e2e/run_test.go b/test/e2e/run_test.go
@@ -1072,4 +1072,13 @@ USER mail`
 		Expect(session.OutputToString()).To(ContainSubstring(h))
 
 	})
+
+	It("podman run verify pids-limit", func() {
+		SkipIfCgroupV1()
+		limit := "4321"
+		session := podmanTest.Podman([]string{"run", "--pids-limit", limit, "--rm", ALPINE, "cat", "/sys/fs/cgroup/pids.max"})
+		session.WaitWithDefaultTimeout()
+		Expect(session.ExitCode()).To(Equal(0))
+		Expect(session.OutputToString()).To(ContainSubstring(limit))
+	})
 })