Merge release-20200219.0-122-g6fa5cee (automated)

16 files changed, 90 insertions, 34 deletions

diff --git a/pkg/sentry/fs/dirent_cache.go b/pkg/sentry/fs/dirent_cache.go
index 25514ace4..33de32c69 100644
--- a/pkg/sentry/fs/dirent_cache.go
+++ b/pkg/sentry/fs/dirent_cache.go
@@ -101,8 +101,6 @@ func (c *DirentCache) remove(d *Dirent) {
 		panic(fmt.Sprintf("trying to remove %v, which is not in the dirent cache", d))
 	}
 	c.list.Remove(d)
-	d.SetPrev(nil)
-	d.SetNext(nil)
 	d.DecRef()
 	c.currentSize--
 	if c.limit != nil {
diff --git a/pkg/sentry/fs/dirent_list.go b/pkg/sentry/fs/dirent_list.go
index 49d25da6c..acdce100c 100755
--- a/pkg/sentry/fs/dirent_list.go
+++ b/pkg/sentry/fs/dirent_list.go
@@ -135,8 +135,9 @@ func (l *direntList) InsertBefore(a, e *Dirent) {
 
 // Remove removes e from l.
 func (l *direntList) Remove(e *Dirent) {
-	prev := direntElementMapper{}.linkerFor(e).Prev()
-	next := direntElementMapper{}.linkerFor(e).Next()
+	linker := direntElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		direntElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *direntList) Remove(e *Dirent) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/fs/event_list.go b/pkg/sentry/fs/event_list.go
index 786686592..0274f41a2 100755
--- a/pkg/sentry/fs/event_list.go
+++ b/pkg/sentry/fs/event_list.go
@@ -135,8 +135,9 @@ func (l *eventList) InsertBefore(a, e *Event) {
 
 // Remove removes e from l.
 func (l *eventList) Remove(e *Event) {
-	prev := eventElementMapper{}.linkerFor(e).Prev()
-	next := eventElementMapper{}.linkerFor(e).Next()
+	linker := eventElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		eventElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *eventList) Remove(e *Event) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/fs/inotify.go b/pkg/sentry/fs/inotify.go
index 928c90aa0..e3a715c1f 100644
--- a/pkg/sentry/fs/inotify.go
+++ b/pkg/sentry/fs/inotify.go
@@ -143,7 +143,10 @@ func (i *Inotify) Read(ctx context.Context, _ *File, dst usermem.IOSequence, _ i
 	}
 
 	var writeLen int64
-	for event := i.events.Front(); event != nil; event = event.Next() {
+	for it := i.events.Front(); it != nil; {
+		event := it
+		it = it.Next()
+
 		// Does the buffer have enough remaining space to hold the event we're
 		// about to write out?
 		if dst.NumBytes() < int64(event.sizeOf()) {
diff --git a/pkg/sentry/kernel/epoll/epoll_list.go b/pkg/sentry/kernel/epoll/epoll_list.go
index 5ac854e38..37f757fa8 100755
--- a/pkg/sentry/kernel/epoll/epoll_list.go
+++ b/pkg/sentry/kernel/epoll/epoll_list.go
@@ -135,8 +135,9 @@ func (l *pollEntryList) InsertBefore(a, e *pollEntry) {
 
 // Remove removes e from l.
 func (l *pollEntryList) Remove(e *pollEntry) {
-	prev := pollEntryElementMapper{}.linkerFor(e).Prev()
-	next := pollEntryElementMapper{}.linkerFor(e).Next()
+	linker := pollEntryElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		pollEntryElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *pollEntryList) Remove(e *pollEntry) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/epoll/epoll_state.go b/pkg/sentry/kernel/epoll/epoll_state.go
index a0d35d350..8e9f200d0 100644
--- a/pkg/sentry/kernel/epoll/epoll_state.go
+++ b/pkg/sentry/kernel/epoll/epoll_state.go
@@ -38,11 +38,14 @@ func (e *EventPoll) afterLoad() {
 		}
 	}
 
-	for it := e.waitingList.Front(); it != nil; it = it.Next() {
-		if it.id.File.Readiness(it.mask) != 0 {
-			e.waitingList.Remove(it)
-			e.readyList.PushBack(it)
-			it.curList = &e.readyList
+	for it := e.waitingList.Front(); it != nil; {
+		entry := it
+		it = it.Next()
+
+		if entry.id.File.Readiness(entry.mask) != 0 {
+			e.waitingList.Remove(entry)
+			e.readyList.PushBack(entry)
+			entry.curList = &e.readyList
 			e.Notify(waiter.EventIn)
 		}
 	}
diff --git a/pkg/sentry/kernel/futex/waiter_list.go b/pkg/sentry/kernel/futex/waiter_list.go
index b6baa1b5b..204eededf 100755
--- a/pkg/sentry/kernel/futex/waiter_list.go
+++ b/pkg/sentry/kernel/futex/waiter_list.go
@@ -135,8 +135,9 @@ func (l *waiterList) InsertBefore(a, e *Waiter) {
 
 // Remove removes e from l.
 func (l *waiterList) Remove(e *Waiter) {
-	prev := waiterElementMapper{}.linkerFor(e).Prev()
-	next := waiterElementMapper{}.linkerFor(e).Next()
+	linker := waiterElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		waiterElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *waiterList) Remove(e *Waiter) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/pending_signals_list.go b/pkg/sentry/kernel/pending_signals_list.go
index 26b9ffd98..8eb40ac2c 100755
--- a/pkg/sentry/kernel/pending_signals_list.go
+++ b/pkg/sentry/kernel/pending_signals_list.go
@@ -135,8 +135,9 @@ func (l *pendingSignalList) InsertBefore(a, e *pendingSignal) {
 
 // Remove removes e from l.
 func (l *pendingSignalList) Remove(e *pendingSignal) {
-	prev := pendingSignalElementMapper{}.linkerFor(e).Prev()
-	next := pendingSignalElementMapper{}.linkerFor(e).Next()
+	linker := pendingSignalElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		pendingSignalElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *pendingSignalList) Remove(e *pendingSignal) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/process_group_list.go b/pkg/sentry/kernel/process_group_list.go
index 2c5363c69..40c1a13a4 100755
--- a/pkg/sentry/kernel/process_group_list.go
+++ b/pkg/sentry/kernel/process_group_list.go
@@ -135,8 +135,9 @@ func (l *processGroupList) InsertBefore(a, e *ProcessGroup) {
 
 // Remove removes e from l.
 func (l *processGroupList) Remove(e *ProcessGroup) {
-	prev := processGroupElementMapper{}.linkerFor(e).Prev()
-	next := processGroupElementMapper{}.linkerFor(e).Next()
+	linker := processGroupElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		processGroupElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *processGroupList) Remove(e *ProcessGroup) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/semaphore/waiter_list.go b/pkg/sentry/kernel/semaphore/waiter_list.go
index 78d86900a..27120afe3 100755
--- a/pkg/sentry/kernel/semaphore/waiter_list.go
+++ b/pkg/sentry/kernel/semaphore/waiter_list.go
@@ -135,8 +135,9 @@ func (l *waiterList) InsertBefore(a, e *waiter) {
 
 // Remove removes e from l.
 func (l *waiterList) Remove(e *waiter) {
-	prev := waiterElementMapper{}.linkerFor(e).Prev()
-	next := waiterElementMapper{}.linkerFor(e).Next()
+	linker := waiterElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		waiterElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *waiterList) Remove(e *waiter) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/session_list.go b/pkg/sentry/kernel/session_list.go
index e65688f53..8174f413d 100755
--- a/pkg/sentry/kernel/session_list.go
+++ b/pkg/sentry/kernel/session_list.go
@@ -135,8 +135,9 @@ func (l *sessionList) InsertBefore(a, e *Session) {
 
 // Remove removes e from l.
 func (l *sessionList) Remove(e *Session) {
-	prev := sessionElementMapper{}.linkerFor(e).Prev()
-	next := sessionElementMapper{}.linkerFor(e).Next()
+	linker := sessionElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		sessionElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *sessionList) Remove(e *Session) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/socket_list.go b/pkg/sentry/kernel/socket_list.go
index a3d47e381..ac93e2365 100755
--- a/pkg/sentry/kernel/socket_list.go
+++ b/pkg/sentry/kernel/socket_list.go
@@ -135,8 +135,9 @@ func (l *socketList) InsertBefore(a, e *SocketEntry) {
 
 // Remove removes e from l.
 func (l *socketList) Remove(e *SocketEntry) {
-	prev := socketElementMapper{}.linkerFor(e).Prev()
-	next := socketElementMapper{}.linkerFor(e).Next()
+	linker := socketElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		socketElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *socketList) Remove(e *SocketEntry) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/kernel/task_list.go b/pkg/sentry/kernel/task_list.go
index 9b8f07b46..4dfcdbf2c 100755
--- a/pkg/sentry/kernel/task_list.go
+++ b/pkg/sentry/kernel/task_list.go
@@ -135,8 +135,9 @@ func (l *taskList) InsertBefore(a, e *Task) {
 
 // Remove removes e from l.
 func (l *taskList) Remove(e *Task) {
-	prev := taskElementMapper{}.linkerFor(e).Prev()
-	next := taskElementMapper{}.linkerFor(e).Next()
+	linker := taskElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		taskElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *taskList) Remove(e *Task) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/mm/io_list.go b/pkg/sentry/mm/io_list.go
index ecb9d4b04..287e4305c 100755
--- a/pkg/sentry/mm/io_list.go
+++ b/pkg/sentry/mm/io_list.go
@@ -135,8 +135,9 @@ func (l *ioList) InsertBefore(a, e *ioResult) {
 
 // Remove removes e from l.
 func (l *ioList) Remove(e *ioResult) {
-	prev := ioElementMapper{}.linkerFor(e).Prev()
-	next := ioElementMapper{}.linkerFor(e).Next()
+	linker := ioElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		ioElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *ioList) Remove(e *ioResult) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/socket/unix/transport/transport_message_list.go b/pkg/sentry/socket/unix/transport/transport_message_list.go
index 565a821bd..9edc731b4 100755
--- a/pkg/sentry/socket/unix/transport/transport_message_list.go
+++ b/pkg/sentry/socket/unix/transport/transport_message_list.go
@@ -135,8 +135,9 @@ func (l *messageList) InsertBefore(a, e *message) {
 
 // Remove removes e from l.
 func (l *messageList) Remove(e *message) {
-	prev := messageElementMapper{}.linkerFor(e).Prev()
-	next := messageElementMapper{}.linkerFor(e).Next()
+	linker := messageElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		messageElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *messageList) Remove(e *message) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields
diff --git a/pkg/sentry/vfs/epoll_interest_list.go b/pkg/sentry/vfs/epoll_interest_list.go
index 011373f0f..1bd41f400 100755
--- a/pkg/sentry/vfs/epoll_interest_list.go
+++ b/pkg/sentry/vfs/epoll_interest_list.go
@@ -135,8 +135,9 @@ func (l *epollInterestList) InsertBefore(a, e *epollInterest) {
 
 // Remove removes e from l.
 func (l *epollInterestList) Remove(e *epollInterest) {
-	prev := epollInterestElementMapper{}.linkerFor(e).Prev()
-	next := epollInterestElementMapper{}.linkerFor(e).Next()
+	linker := epollInterestElementMapper{}.linkerFor(e)
+	prev := linker.Prev()
+	next := linker.Next()
 
 	if prev != nil {
 		epollInterestElementMapper{}.linkerFor(prev).SetNext(next)
@@ -149,6 +150,9 @@ func (l *epollInterestList) Remove(e *epollInterest) {
 	} else {
 		l.tail = prev
 	}
+
+	linker.SetNext(nil)
+	linker.SetPrev(nil)
 }
 
 // Entry is a default implementation of Linker. Users can add anonymous fields