diff options
author | gVisor bot <gvisor-bot@google.com> | 2020-11-09 16:36:50 +0000 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2020-11-09 16:36:50 +0000 |
commit | 7dd056ef81a67dc95b3d079f20e58e771498220c (patch) | |
tree | f8a73367fa610fb309e60c7b8ffdddd13e6a6835 /pkg/sentry/kernel/fd_table_refs.go | |
parent | 9e848922ed33f78bddbb7a772dceba5406c185a2 (diff) | |
parent | 0fb5353e45f166460d5846576c20479072207a06 (diff) |
Merge release-20201030.0-53-g0fb5353e4 (automated)
Diffstat (limited to 'pkg/sentry/kernel/fd_table_refs.go')
-rw-r--r-- | pkg/sentry/kernel/fd_table_refs.go | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/pkg/sentry/kernel/fd_table_refs.go b/pkg/sentry/kernel/fd_table_refs.go index 992606f36..f540ba371 100644 --- a/pkg/sentry/kernel/fd_table_refs.go +++ b/pkg/sentry/kernel/fd_table_refs.go @@ -20,9 +20,6 @@ var FDTableobj *FDTable // Refs implements refs.RefCounter. It keeps a reference count using atomic // operations and calls the destructor when the count reaches zero. // -// Note that the number of references is actually refCount + 1 so that a default -// zero-value Refs object contains one reference. -// // +stateify savable type FDTableRefs struct { // refCount is composed of two fields: @@ -35,6 +32,13 @@ type FDTableRefs struct { refCount int64 } +// InitRefs initializes r with one reference and, if enabled, activates leak +// checking. +func (r *FDTableRefs) InitRefs() { + atomic.StoreInt64(&r.refCount, 1) + refsvfs2.Register(r) +} + // RefType implements refsvfs2.CheckedObject.RefType. func (r *FDTableRefs) RefType() string { return fmt.Sprintf("%T", FDTableobj)[1:] @@ -58,8 +62,7 @@ func (r *FDTableRefs) EnableLeakCheck() { // ReadRefs returns the current number of references. The returned count is // inherently racy and is unsafe to use without external synchronization. func (r *FDTableRefs) ReadRefs() int64 { - - return atomic.LoadInt64(&r.refCount) + 1 + return atomic.LoadInt64(&r.refCount) } // IncRef implements refs.RefCounter.IncRef. @@ -67,8 +70,10 @@ func (r *FDTableRefs) ReadRefs() int64 { //go:nosplit func (r *FDTableRefs) IncRef() { v := atomic.AddInt64(&r.refCount, 1) - refsvfs2.LogIncRef(r, v+1) - if v <= 0 { + if FDTableenableLogging { + refsvfs2.LogIncRef(r, v) + } + if v <= 1 { panic(fmt.Sprintf("Incrementing non-positive count %p on %s", r, r.RefType())) } } @@ -82,14 +87,16 @@ func (r *FDTableRefs) IncRef() { //go:nosplit func (r *FDTableRefs) TryIncRef() bool { const speculativeRef = 1 << 32 - if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) < 0 { + if v := atomic.AddInt64(&r.refCount, speculativeRef); int32(v) == 0 { atomic.AddInt64(&r.refCount, -speculativeRef) return false } v := atomic.AddInt64(&r.refCount, -speculativeRef+1) - refsvfs2.LogTryIncRef(r, v+1) + if FDTableenableLogging { + refsvfs2.LogTryIncRef(r, v) + } return true } @@ -107,12 +114,14 @@ func (r *FDTableRefs) TryIncRef() bool { //go:nosplit func (r *FDTableRefs) DecRef(destroy func()) { v := atomic.AddInt64(&r.refCount, -1) - refsvfs2.LogDecRef(r, v+1) + if FDTableenableLogging { + refsvfs2.LogDecRef(r, v+1) + } switch { - case v < -1: + case v < 0: panic(fmt.Sprintf("Decrementing non-positive ref count %p, owned by %s", r, r.RefType())) - case v == -1: + case v == 0: refsvfs2.Unregister(r) if destroy != nil { |