From 25798f214c6d1991916906ea8fca9e7029a8c423 Mon Sep 17 00:00:00 2001
From: Andrei Vagin <avagin@google.com>
Date: Mon, 3 Aug 2020 22:06:46 -0700
Subject: Add callbacks to support lazy loading/restoring thread states

PiperOrigin-RevId: 324748508
---
 pkg/sentry/mm/lifecycle.go | 2 ++
 pkg/sentry/mm/vma.go       | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

(limited to 'pkg/sentry/mm')

diff --git a/pkg/sentry/mm/lifecycle.go b/pkg/sentry/mm/lifecycle.go
index 4d7773f8b..09dbc06a4 100644
--- a/pkg/sentry/mm/lifecycle.go
+++ b/pkg/sentry/mm/lifecycle.go
@@ -57,6 +57,8 @@ func (mm *MemoryManager) SetMmapLayout(ac arch.Context, r *limits.LimitSet) (arc
 // Fork creates a copy of mm with 1 user, as for Linux syscalls fork() or
 // clone() (without CLONE_VM).
 func (mm *MemoryManager) Fork(ctx context.Context) (*MemoryManager, error) {
+	mm.AddressSpace().PreFork()
+	defer mm.AddressSpace().PostFork()
 	mm.metadataMu.Lock()
 	defer mm.metadataMu.Unlock()
 	mm.mappingMu.RLock()
diff --git a/pkg/sentry/mm/vma.go b/pkg/sentry/mm/vma.go
index bd751d696..c4e1989ed 100644
--- a/pkg/sentry/mm/vma.go
+++ b/pkg/sentry/mm/vma.go
@@ -42,7 +42,12 @@ func (mm *MemoryManager) createVMALocked(ctx context.Context, opts memmap.MMapOp
 		Map32Bit: opts.Map32Bit,
 	})
 	if err != nil {
-		return vmaIterator{}, usermem.AddrRange{}, err
+		// Can't force without opts.Unmap and opts.Fixed.
+		if opts.Force && opts.Unmap && opts.Fixed {
+			addr = opts.Addr
+		} else {
+			return vmaIterator{}, usermem.AddrRange{}, err
+		}
 	}
 	ar, _ := addr.ToRange(opts.Length)
 
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