Extend MAP_GROWSDOWN mappings to their correct start address.
diff --git a/src/AutoRemoteSyscalls.cc b/src/AutoRemoteSyscalls.cc
index 010564a..8eb9c8b 100644
--- a/src/AutoRemoteSyscalls.cc
+++ b/src/AutoRemoteSyscalls.cc
@@ -74,6 +74,11 @@
}
}
+static bool is_usable_area(const KernelMapping& km) {
+ return (km.prot() & (PROT_READ | PROT_WRITE)) == (PROT_READ | PROT_WRITE) &&
+ (km.flags() & MAP_PRIVATE);
+}
+
void AutoRemoteSyscalls::maybe_fix_stack_pointer() {
if (!t->session().can_validate()) {
return;
@@ -82,8 +87,7 @@
remote_ptr<void> last_stack_byte = t->regs().sp() - 1;
if (t->vm()->has_mapping(last_stack_byte)) {
auto m = t->vm()->mapping_of(last_stack_byte);
- if (m.recorded_map.is_stack() &&
- m.recorded_map.start() + 1024 <= t->regs().sp()) {
+ if (is_usable_area(m.map) && m.map.start() + 2048 <= t->regs().sp()) {
// 'sp' is in a stack region and there's plenty of space there. No need
// to fix anything.
return;
@@ -92,8 +96,9 @@
MemoryRange found_stack;
for (auto m : t->vm()->maps()) {
- if (m.recorded_map.is_stack()) {
- found_stack = m.recorded_map;
+ if (is_usable_area(m.map)) {
+ found_stack = m.map;
+ break;
}
};
ASSERT(t, !found_stack.start().is_null()) << "No stack area found";
