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authorgVisor bot <gvisor-bot@google.com>2020-10-29 01:29:16 +0000
committergVisor bot <gvisor-bot@google.com>2020-10-29 01:29:16 +0000
commita50cfffd384c07e11b5d3ad21f3a096bf1ff4521 (patch)
tree9a0f389bd874a44d32d9729c118e4f338d92d198 /pkg/sentry/kernel/session_refs.go
parent0cc41c9357ae7c1db41ad74f2830253c42b007ce (diff)
parent3b4674ffe0e6ef1b016333ee726293ecf70c4e4e (diff)
Merge release-20201019.0-95-g3b4674ffe (automated)
Diffstat (limited to 'pkg/sentry/kernel/session_refs.go')
-rw-r--r--pkg/sentry/kernel/session_refs.go56
1 files changed, 36 insertions, 20 deletions
diff --git a/pkg/sentry/kernel/session_refs.go b/pkg/sentry/kernel/session_refs.go
index 86df93be1..430cb131c 100644
--- a/pkg/sentry/kernel/session_refs.go
+++ b/pkg/sentry/kernel/session_refs.go
@@ -7,9 +7,15 @@ import (
"gvisor.dev/gvisor/pkg/refsvfs2"
)
-// ownerType is used to customize logging. Note that we use a pointer to T so
-// that we do not copy the entire object when passed as a format parameter.
-var SessionownerType *Session
+// enableLogging indicates whether reference-related events should be logged (with
+// stack traces). This is false by default and should only be set to true for
+// debugging purposes, as it can generate an extremely large amount of output
+// and drastically degrade performance.
+const SessionenableLogging = false
+
+// obj is used to customize logging. Note that we use a pointer to T so that
+// we do not copy the entire object when passed as a format parameter.
+var Sessionobj *Session
// Refs implements refs.RefCounter. It keeps a reference count using atomic
// operations and calls the destructor when the count reaches zero.
@@ -29,16 +35,24 @@ type SessionRefs struct {
refCount int64
}
-// EnableLeakCheck enables reference leak checking on r.
-func (r *SessionRefs) EnableLeakCheck() {
- if refsvfs2.LeakCheckEnabled() {
- refsvfs2.Register(r, fmt.Sprintf("%T", SessionownerType))
- }
+// RefType implements refsvfs2.CheckedObject.RefType.
+func (r *SessionRefs) RefType() string {
+ return fmt.Sprintf("%T", Sessionobj)[1:]
}
// LeakMessage implements refsvfs2.CheckedObject.LeakMessage.
func (r *SessionRefs) LeakMessage() string {
- return fmt.Sprintf("%T %p: reference count of %d instead of 0", SessionownerType, r, r.ReadRefs())
+ return fmt.Sprintf("[%s %p] reference count of %d instead of 0", r.RefType(), r, r.ReadRefs())
+}
+
+// LogRefs implements refsvfs2.CheckedObject.LogRefs.
+func (r *SessionRefs) LogRefs() bool {
+ return SessionenableLogging
+}
+
+// EnableLeakCheck enables reference leak checking on r.
+func (r *SessionRefs) EnableLeakCheck() {
+ refsvfs2.Register(r)
}
// ReadRefs returns the current number of references. The returned count is
@@ -52,8 +66,10 @@ func (r *SessionRefs) ReadRefs() int64 {
//
//go:nosplit
func (r *SessionRefs) IncRef() {
- if v := atomic.AddInt64(&r.refCount, 1); v <= 0 {
- panic(fmt.Sprintf("Incrementing non-positive count %p on %T", r, SessionownerType))
+ v := atomic.AddInt64(&r.refCount, 1)
+ refsvfs2.LogIncRef(r, v+1)
+ if v <= 0 {
+ panic(fmt.Sprintf("Incrementing non-positive count %p on %s", r, r.RefType()))
}
}
@@ -66,14 +82,14 @@ func (r *SessionRefs) IncRef() {
//go:nosplit
func (r *SessionRefs) TryIncRef() bool {
const speculativeRef = 1 << 32
- v := atomic.AddInt64(&r.refCount, speculativeRef)
- if int32(v) < 0 {
+ if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) < 0 {
atomic.AddInt64(&r.refCount, -speculativeRef)
return false
}
- atomic.AddInt64(&r.refCount, -speculativeRef+1)
+ v := atomic.AddInt64(&r.refCount, -speculativeRef+1)
+ refsvfs2.LogTryIncRef(r, v+1)
return true
}
@@ -90,14 +106,14 @@ func (r *SessionRefs) TryIncRef() bool {
//
//go:nosplit
func (r *SessionRefs) DecRef(destroy func()) {
- switch v := atomic.AddInt64(&r.refCount, -1); {
+ v := atomic.AddInt64(&r.refCount, -1)
+ refsvfs2.LogDecRef(r, v+1)
+ switch {
case v < -1:
- panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %T", r, SessionownerType))
+ panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %s", r, r.RefType()))
case v == -1:
- if refsvfs2.LeakCheckEnabled() {
- refsvfs2.Unregister(r, fmt.Sprintf("%T", SessionownerType))
- }
+ refsvfs2.Unregister(r)
if destroy != nil {
destroy()
@@ -106,7 +122,7 @@ func (r *SessionRefs) DecRef(destroy func()) {
}
func (r *SessionRefs) afterLoad() {
- if refsvfs2.LeakCheckEnabled() && r.ReadRefs() > 0 {
+ if r.ReadRefs() > 0 {
r.EnableLeakCheck()
}
}