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authorFabricio Voznika <fvoznika@google.com>2020-02-25 13:42:34 -0800
committergVisor bot <gvisor-bot@google.com>2020-02-25 13:44:18 -0800
commit72e3f3a3eef3a1dc02db0ff71f98a5d7fe89a6e3 (patch)
tree54d520df721a706fdffabda9e6c560b197cdee86
parent430992a67abe30dc6cb4e00822517c0aed388088 (diff)
Add option to skip stuck tasks waiting for address space
PiperOrigin-RevId: 297192390
-rw-r--r--pkg/sentry/kernel/kernel.go4
-rw-r--r--pkg/sentry/kernel/task_context.go2
-rw-r--r--pkg/sentry/kernel/task_exec.go2
-rw-r--r--pkg/sentry/kernel/task_usermem.go2
-rw-r--r--pkg/sentry/mm/address_space.go23
-rw-r--r--pkg/sentry/mm/lifecycle.go26
-rw-r--r--pkg/sentry/mm/mm.go5
-rw-r--r--pkg/sentry/mm/mm_test.go2
8 files changed, 41 insertions, 25 deletions
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index c62fd6eb1..8b76750e9 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -247,6 +247,10 @@ type Kernel struct {
// VFS keeps the filesystem state used across the kernel.
vfs vfs.VirtualFilesystem
+
+ // If set to true, report address space activation waits as if the task is in
+ // external wait so that the watchdog doesn't report the task stuck.
+ SleepForAddressSpaceActivation bool
}
// InitKernelArgs holds arguments to Init.
diff --git a/pkg/sentry/kernel/task_context.go b/pkg/sentry/kernel/task_context.go
index 2be982684..0158b1788 100644
--- a/pkg/sentry/kernel/task_context.go
+++ b/pkg/sentry/kernel/task_context.go
@@ -140,7 +140,7 @@ func (k *Kernel) LoadTaskImage(ctx context.Context, args loader.LoadArgs) (*Task
}
// Prepare a new user address space to load into.
- m := mm.NewMemoryManager(k, k)
+ m := mm.NewMemoryManager(k, k, k.SleepForAddressSpaceActivation)
defer m.DecUsers(ctx)
args.MemoryManager = m
diff --git a/pkg/sentry/kernel/task_exec.go b/pkg/sentry/kernel/task_exec.go
index 8f57a34a6..00c425cca 100644
--- a/pkg/sentry/kernel/task_exec.go
+++ b/pkg/sentry/kernel/task_exec.go
@@ -220,7 +220,7 @@ func (r *runSyscallAfterExecStop) execute(t *Task) taskRunState {
t.mu.Unlock()
t.unstopVforkParent()
// NOTE(b/30316266): All locks must be dropped prior to calling Activate.
- t.MemoryManager().Activate()
+ t.MemoryManager().Activate(t)
t.ptraceExec(oldTID)
return (*runSyscallExit)(nil)
diff --git a/pkg/sentry/kernel/task_usermem.go b/pkg/sentry/kernel/task_usermem.go
index 2bf3ce8a8..b02044ad2 100644
--- a/pkg/sentry/kernel/task_usermem.go
+++ b/pkg/sentry/kernel/task_usermem.go
@@ -30,7 +30,7 @@ var MAX_RW_COUNT = int(usermem.Addr(math.MaxInt32).RoundDown())
// Activate ensures that the task has an active address space.
func (t *Task) Activate() {
if mm := t.MemoryManager(); mm != nil {
- if err := mm.Activate(); err != nil {
+ if err := mm.Activate(t); err != nil {
panic("unable to activate mm: " + err.Error())
}
}
diff --git a/pkg/sentry/mm/address_space.go b/pkg/sentry/mm/address_space.go
index 94d39af60..0332fc71c 100644
--- a/pkg/sentry/mm/address_space.go
+++ b/pkg/sentry/mm/address_space.go
@@ -18,6 +18,7 @@ import (
"fmt"
"sync/atomic"
+ "gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/sentry/platform"
"gvisor.dev/gvisor/pkg/usermem"
)
@@ -38,7 +39,7 @@ func (mm *MemoryManager) AddressSpace() platform.AddressSpace {
//
// When this MemoryManager is no longer needed by a task, it should call
// Deactivate to release the reference.
-func (mm *MemoryManager) Activate() error {
+func (mm *MemoryManager) Activate(ctx context.Context) error {
// Fast path: the MemoryManager already has an active
// platform.AddressSpace, and we just need to indicate that we need it too.
for {
@@ -91,16 +92,20 @@ func (mm *MemoryManager) Activate() error {
if as == nil {
// AddressSpace is unavailable, we must wait.
//
- // activeMu must not be held while waiting, as the user
- // of the address space we are waiting on may attempt
- // to take activeMu.
- //
- // Don't call UninterruptibleSleepStart to register the
- // wait to allow the watchdog stuck task to trigger in
- // case a process is starved waiting for the address
- // space.
+ // activeMu must not be held while waiting, as the user of the address
+ // space we are waiting on may attempt to take activeMu.
mm.activeMu.Unlock()
+
+ sleep := mm.p.CooperativelySchedulesAddressSpace() && mm.sleepForActivation
+ if sleep {
+ // Mark this task sleeping while waiting for the address space to
+ // prevent the watchdog from reporting it as a stuck task.
+ ctx.UninterruptibleSleepStart(false)
+ }
<-c
+ if sleep {
+ ctx.UninterruptibleSleepFinish(false)
+ }
continue
}
diff --git a/pkg/sentry/mm/lifecycle.go b/pkg/sentry/mm/lifecycle.go
index 3c263ebaa..d8a5b9d29 100644
--- a/pkg/sentry/mm/lifecycle.go
+++ b/pkg/sentry/mm/lifecycle.go
@@ -28,16 +28,17 @@ import (
)
// NewMemoryManager returns a new MemoryManager with no mappings and 1 user.
-func NewMemoryManager(p platform.Platform, mfp pgalloc.MemoryFileProvider) *MemoryManager {
+func NewMemoryManager(p platform.Platform, mfp pgalloc.MemoryFileProvider, sleepForActivation bool) *MemoryManager {
return &MemoryManager{
- p: p,
- mfp: mfp,
- haveASIO: p.SupportsAddressSpaceIO(),
- privateRefs: &privateRefs{},
- users: 1,
- auxv: arch.Auxv{},
- dumpability: UserDumpable,
- aioManager: aioManager{contexts: make(map[uint64]*AIOContext)},
+ p: p,
+ mfp: mfp,
+ haveASIO: p.SupportsAddressSpaceIO(),
+ privateRefs: &privateRefs{},
+ users: 1,
+ auxv: arch.Auxv{},
+ dumpability: UserDumpable,
+ aioManager: aioManager{contexts: make(map[uint64]*AIOContext)},
+ sleepForActivation: sleepForActivation,
}
}
@@ -79,9 +80,10 @@ func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error) {
envv: mm.envv,
auxv: append(arch.Auxv(nil), mm.auxv...),
// IncRef'd below, once we know that there isn't an error.
- executable: mm.executable,
- dumpability: mm.dumpability,
- aioManager: aioManager{contexts: make(map[uint64]*AIOContext)},
+ executable: mm.executable,
+ dumpability: mm.dumpability,
+ aioManager: aioManager{contexts: make(map[uint64]*AIOContext)},
+ sleepForActivation: mm.sleepForActivation,
}
// Copy vmas.
diff --git a/pkg/sentry/mm/mm.go b/pkg/sentry/mm/mm.go
index 637383c7a..c2195ae11 100644
--- a/pkg/sentry/mm/mm.go
+++ b/pkg/sentry/mm/mm.go
@@ -226,6 +226,11 @@ type MemoryManager struct {
// aioManager keeps track of AIOContexts used for async IOs. AIOManager
// must be cloned when CLONE_VM is used.
aioManager aioManager
+
+ // sleepForActivation indicates whether the task should report to be sleeping
+ // before trying to activate the address space. When set to true, delays in
+ // activation are not reported as stuck tasks by the watchdog.
+ sleepForActivation bool
}
// vma represents a virtual memory area.
diff --git a/pkg/sentry/mm/mm_test.go b/pkg/sentry/mm/mm_test.go
index edacca741..fdc308542 100644
--- a/pkg/sentry/mm/mm_test.go
+++ b/pkg/sentry/mm/mm_test.go
@@ -31,7 +31,7 @@ import (
func testMemoryManager(ctx context.Context) *MemoryManager {
p := platform.FromContext(ctx)
mfp := pgalloc.MemoryFileProviderFromContext(ctx)
- mm := NewMemoryManager(p, mfp)
+ mm := NewMemoryManager(p, mfp, false)
mm.layout = arch.MmapLayout{
MinAddr: p.MinUserAddress(),
MaxAddr: p.MaxUserAddress(),