mossberg updated this revision to Diff 233708.
mossberg added a comment.
Add test.
I wasn't sure where to put it, so I left it in the `Unwind/` directory since
the `call-asm.c` infrastructure is already there, and this fix is *kind of*
vaguely related to unwinding. Please let me know if there's a better location.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D71372/new/
https://reviews.llvm.org/D71372
Files:
lldb/include/lldb/Target/ThreadPlanStepOut.h
lldb/source/Target/ThreadPlanStepOut.cpp
lldb/test/Shell/Unwind/Inputs/thread-step-out-ret-addr-check.s
lldb/test/Shell/Unwind/thread-step-out-ret-addr-check.test
Index: lldb/test/Shell/Unwind/thread-step-out-ret-addr-check.test
===================================================================
--- /dev/null
+++ lldb/test/Shell/Unwind/thread-step-out-ret-addr-check.test
@@ -0,0 +1,17 @@
+# Test that `thread step-out` fails when the "return address"
+# points to non-executable memory.
+
+# REQUIRES: target-x86_64, native
+
+# RUN: %clang_host %p/Inputs/call-asm.c %p/Inputs/thread-step-out-ret-addr-check.s -o %t
+# RUN: %lldb %t -s %s -b 2>&1 | FileCheck %s
+
+breakpoint set -n nonstandard_stub
+# CHECK: Breakpoint 1: where = {{.*}}`nonstandard_stub
+
+process launch
+# CHECK: stop reason = breakpoint 1.1
+
+thread step-out
+# CHECK: Could not create return address breakpoint.
+# CHECK: Return address (0x{{[a-f0-9]*}}) did not point to executable memory.
Index: lldb/test/Shell/Unwind/Inputs/thread-step-out-ret-addr-check.s
===================================================================
--- /dev/null
+++ lldb/test/Shell/Unwind/Inputs/thread-step-out-ret-addr-check.s
@@ -0,0 +1,20 @@
+ .text
+ .globl asm_main
+asm_main:
+ sub $0x8, %rsp
+ movq $0, (%rsp)
+ push %rsp
+ jmp _nonstandard_stub
+
+# Takes a single pointer argument via the stack, which is nonstandard for x64.
+# Executing 'thread step-out' here will initially attempt to write a
+# breakpoint to that stack address, but should fail because of the executable
+# memory check.
+_nonstandard_stub:
+ mov (%rsp), %rdi
+ mov (%rdi), %rsi
+ add $1, %rsi
+ mov %rsi, (%rdi)
+
+ add $0x10, %rsp
+ ret
Index: lldb/source/Target/ThreadPlanStepOut.cpp
===================================================================
--- lldb/source/Target/ThreadPlanStepOut.cpp
+++ lldb/source/Target/ThreadPlanStepOut.cpp
@@ -126,6 +126,25 @@
if (m_return_addr == LLDB_INVALID_ADDRESS)
return;
+ // Perform some additional validation on the return address.
+ uint32_t permissions = 0;
+ if (!m_thread.GetProcess()->GetLoadAddressPermissions(m_return_addr,
+ permissions)) {
+ m_constructor_errors.Printf("Return address (0x%" PRIx64
+ ") permissions not found.",
+ m_return_addr);
+ LLDB_LOGF(log, "ThreadPlanStepOut(%p): %s", static_cast<void *>(this),
+ m_constructor_errors.GetData());
+ return;
+ } else if (!(permissions & ePermissionsExecutable)) {
+ m_constructor_errors.Printf("Return address (0x%" PRIx64
+ ") did not point to executable memory.",
+ m_return_addr);
+ LLDB_LOGF(log, "ThreadPlanStepOut(%p): %s", static_cast<void *>(this),
+ m_constructor_errors.GetData());
+ return;
+ }
+
Breakpoint *return_bp = m_thread.CalculateTarget()
->CreateBreakpoint(m_return_addr, true, false)
.get();
@@ -238,8 +257,13 @@
}
if (m_return_bp_id == LLDB_INVALID_BREAK_ID) {
- if (error)
+ if (error) {
error->PutCString("Could not create return address breakpoint.");
+ if (m_constructor_errors.GetSize() > 0) {
+ error->PutCString(" ");
+ error->PutCString(m_constructor_errors.GetString());
+ }
+ }
return false;
}
Index: lldb/include/lldb/Target/ThreadPlanStepOut.h
===================================================================
--- lldb/include/lldb/Target/ThreadPlanStepOut.h
+++ lldb/include/lldb/Target/ThreadPlanStepOut.h
@@ -72,6 +72,7 @@
std::vector<lldb::StackFrameSP> m_stepped_past_frames;
lldb::ValueObjectSP m_return_valobj_sp;
bool m_calculate_return_value;
+ StreamString m_constructor_errors;
friend lldb::ThreadPlanSP Thread::QueueThreadPlanForStepOut(
bool abort_other_plans, SymbolContext *addr_context, bool first_insn,
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