From 80d0f9304484897e4307c9701ddbfaacb925715d Mon Sep 17 00:00:00 2001
From: Nicolas Lacasse <nlacasse@google.com>
Date: Fri, 17 Jan 2020 11:20:29 -0800
Subject: Fix data race in tty.queue.readableSize.
We were setting queue.readable without holding the lock.
PiperOrigin-RevId: 290306922
---
pkg/sentry/fs/tty/line_discipline.go | 4 +++-
pkg/sentry/fs/tty/queue.go | 11 ++---------
2 files changed, 5 insertions(+), 10 deletions(-)
(limited to 'pkg/sentry/fs')
diff --git a/pkg/sentry/fs/tty/line_discipline.go b/pkg/sentry/fs/tty/line_discipline.go
index 894964260..9fe02657e 100644
--- a/pkg/sentry/fs/tty/line_discipline.go
+++ b/pkg/sentry/fs/tty/line_discipline.go
@@ -140,8 +140,10 @@ func (l *lineDiscipline) setTermios(ctx context.Context, io usermem.IO, args arc
// buffer to its read buffer. Anything already in the read buffer is
// now readable.
if oldCanonEnabled && !l.termios.LEnabled(linux.ICANON) {
- l.inQueue.pushWaitBuf(l)
+ l.inQueue.mu.Lock()
+ l.inQueue.pushWaitBufLocked(l)
l.inQueue.readable = true
+ l.inQueue.mu.Unlock()
l.slaveWaiter.Notify(waiter.EventIn)
}
diff --git a/pkg/sentry/fs/tty/queue.go b/pkg/sentry/fs/tty/queue.go
index 8b5d4699a..21ccc6f32 100644
--- a/pkg/sentry/fs/tty/queue.go
+++ b/pkg/sentry/fs/tty/queue.go
@@ -197,16 +197,9 @@ func (q *queue) writeBytes(b []byte, l *lineDiscipline) {
q.pushWaitBufLocked(l)
}
-// pushWaitBuf fills the queue's read buffer with data from the wait buffer.
+// pushWaitBufLocked fills the queue's read buffer with data from the wait
+// buffer.
//
-// Preconditions:
-// * l.termiosMu must be held for reading.
-func (q *queue) pushWaitBuf(l *lineDiscipline) int {
- q.mu.Lock()
- defer q.mu.Unlock()
- return q.pushWaitBufLocked(l)
-}
-
// Preconditions:
// * l.termiosMu must be held for reading.
// * q.mu must be locked.
--
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