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-rw-r--r--src/processor/stackwalker_amd64.cc34
-rw-r--r--src/processor/stackwalker_amd64.h8
-rw-r--r--src/processor/stackwalker_amd64_unittest.cc132
3 files changed, 165 insertions, 9 deletions
diff --git a/src/processor/stackwalker_amd64.cc b/src/processor/stackwalker_amd64.cc
index f252a33b..8ccf73c4 100644
--- a/src/processor/stackwalker_amd64.cc
+++ b/src/processor/stackwalker_amd64.cc
@@ -147,6 +147,23 @@ StackFrameAMD64* StackwalkerAMD64::GetCallerByCFIFrameInfo(
return frame.release();
}
+bool StackwalkerAMD64::IsEndOfStack(uint64_t caller_rip, uint64_t caller_rsp,
+ uint64_t callee_rsp) {
+ // Treat an instruction address of 0 as end-of-stack.
+ if (caller_rip == 0) {
+ return true;
+ }
+
+ // If the new stack pointer is at a lower address than the old, then
+ // that's clearly incorrect. Treat this as end-of-stack to enforce
+ // progress and avoid infinite loops.
+ if (caller_rsp < callee_rsp) {
+ return true;
+ }
+
+ return false;
+}
+
StackFrameAMD64* StackwalkerAMD64::GetCallerByFramePointerRecovery(
const vector<StackFrame*>& frames) {
StackFrameAMD64* last_frame = static_cast<StackFrameAMD64*>(frames.back());
@@ -175,8 +192,11 @@ StackFrameAMD64* StackwalkerAMD64::GetCallerByFramePointerRecovery(
uint64_t caller_rsp = last_rbp + 16;
// Simple sanity check that the stack is growing downwards as expected.
- if (caller_rbp < last_rbp || caller_rsp < last_rsp)
+ if (IsEndOfStack(caller_rip, caller_rsp, last_rsp) ||
+ caller_rbp < last_rbp) {
+ // Reached end-of-stack or stack is not growing downwards.
return NULL;
+ }
StackFrameAMD64* frame = new StackFrameAMD64();
frame->trust = StackFrame::FRAME_TRUST_FP;
@@ -284,15 +304,11 @@ StackFrame* StackwalkerAMD64::GetCallerFrame(const CallStack* stack,
new_frame->context.rbp = static_cast<uint32_t>(new_frame->context.rbp);
}
- // Treat an instruction address of 0 as end-of-stack.
- if (new_frame->context.rip == 0)
- return NULL;
-
- // If the new stack pointer is at a lower address than the old, then
- // that's clearly incorrect. Treat this as end-of-stack to enforce
- // progress and avoid infinite loops.
- if (new_frame->context.rsp <= last_frame->context.rsp)
+ if (IsEndOfStack(new_frame->context.rip, new_frame->context.rsp,
+ last_frame->context.rsp)) {
+ // Reached end-of-stack.
return NULL;
+ }
// new_frame->context.rip is the return address, which is the instruction
// after the CALL that caused us to arrive at the callee. Set
diff --git a/src/processor/stackwalker_amd64.h b/src/processor/stackwalker_amd64.h
index 8f3dbd52..67c45510 100644
--- a/src/processor/stackwalker_amd64.h
+++ b/src/processor/stackwalker_amd64.h
@@ -78,6 +78,14 @@ class StackwalkerAMD64 : public Stackwalker {
StackFrameAMD64* GetCallerByCFIFrameInfo(const vector<StackFrame*> &frames,
CFIFrameInfo* cfi_frame_info);
+ // Checks whether end-of-stack is reached. An instruction address of 0 is an
+ // end-of-stack marker. If the stack pointer of the caller is at a lower
+ // address than the stack pointer of the callee, then that's clearly incorrect
+ // and it is treated as end-of-stack to enforce progress and avoid infinite
+ // loops.
+ bool IsEndOfStack(uint64_t caller_rip, uint64_t caller_rsp,
+ uint64_t callee_rsp);
+
// Assumes a traditional frame layout where the frame pointer has not been
// omitted. The expectation is that caller's %rbp is pushed to the stack
// after the return address of the callee, and that the callee's %rsp can
diff --git a/src/processor/stackwalker_amd64_unittest.cc b/src/processor/stackwalker_amd64_unittest.cc
index a54198bf..23f38f70 100644
--- a/src/processor/stackwalker_amd64_unittest.cc
+++ b/src/processor/stackwalker_amd64_unittest.cc
@@ -370,6 +370,138 @@ TEST_F(GetCallerFrame, ScanWithFunctionSymbols) {
EXPECT_EQ(0x50000000b0000100ULL, frame1->function_base);
}
+// StackwalkerAMD64::GetCallerByFramePointerRecovery should never return an
+// instruction pointer of 0 because IP of 0 is an end of stack marker and the
+// stack walk may be terminated prematurely. Instead it should return NULL
+// so that the stack walking code can proceed to stack scanning.
+TEST_F(GetCallerFrame, GetCallerByFramePointerRecovery) {
+ MockCodeModule user32_dll(0x00007ff9cb8a0000ULL, 0x14E000, "user32.dll",
+ "version1");
+ SetModuleSymbols(&user32_dll, // user32.dll
+ "PUBLIC fa60 0 DispatchMessageWorker\n"
+ "PUBLIC fee0 0 UserCallWinProcCheckWow\n"
+ "PUBLIC 1cdb0 0 _fnHkINLPMSG\n"
+ "STACK CFI INIT fa60 340 .cfa: $rsp .ra: .cfa 8 - ^\n"
+ "STACK CFI fa60 .cfa: $rsp 128 +\n"
+ "STACK CFI INIT fee0 49f .cfa: $rsp .ra: .cfa 8 - ^\n"
+ "STACK CFI fee0 .cfa: $rsp 240 +\n"
+ "STACK CFI INIT 1cdb0 9f .cfa: $rsp .ra: .cfa 8 - ^\n"
+ "STACK CFI 1cdb0 .cfa: $rsp 80 +\n");
+
+ // Create some modules with some stock debugging information.
+ MockCodeModules local_modules;
+ local_modules.Add(&user32_dll);
+
+ Label frame0_rsp;
+ Label frame0_rbp;
+ Label frame1_rsp;
+ Label frame2_rsp;
+
+ stack_section.start() = 0x00000099abf0f238ULL;
+ stack_section
+ .Mark(&frame0_rsp)
+ .D64(0x00007ff9cb8b00dcULL)
+ .Mark(&frame1_rsp)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000001ULL)
+ .D64(0x00000099abf0f308ULL)
+ .D64(0x00007ff9cb8bce3aULL) // Stack residue from execution of
+ // user32!_fnHkINLPMSG+0x8a
+ .D64(0x000000000000c2e0ULL)
+ .D64(0x00000099abf0f328ULL)
+ .D64(0x0000000100000001ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x00007ff9ccad53e4ULL)
+ .D64(0x0000000000000048ULL)
+ .D64(0x0000000000000001ULL)
+ .D64(0x00000099abf0f5e0ULL)
+ .D64(0x00000099b61f7388ULL)
+ .D64(0x0000000000000030ULL)
+ .D64(0xffffff66540f0a1fULL)
+ .D64(0xffffff6649e08c77ULL)
+ .D64(0x00007ff9cb8affb4ULL) // Return address in
+ // user32!UserCallWinProcCheckWow+0xd4
+ .D64(0x0000000000000000ULL)
+ .D64(0x00000099abf0f368ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x0000000000000000ULL)
+ .D64(0x00000099a8150fd8ULL)
+ .D64(0x00000099abf0f3e8ULL)
+ .D64(0x00007ff9cb8afc07ULL) // Return address in
+ // user32!DispatchMessageWorker+0x1a7
+ .Mark(&frame2_rsp)
+ .Append(256, 0)
+ .Mark(&frame0_rbp) // The following are expected by
+ // GetCallerByFramePointerRecovery.
+ .D64(0xfffffffffffffffeULL) // %caller_rbp = *(%callee_rbp)
+ .D64(0x0000000000000000ULL) // %caller_rip = *(%callee_rbp + 8)
+ .D64(0x00000099a3e31040ULL) // %caller_rsp = *(%callee_rbp + 16)
+ .Append(256, 0);
+
+ RegionFromSection();
+ raw_context.rip = 0x00000099a8150fd8ULL; // IP in context frame is guarbage
+ raw_context.rsp = frame0_rsp.Value();
+ raw_context.rbp = frame0_rbp.Value();
+
+ StackFrameSymbolizer frame_symbolizer(&supplier, &resolver);
+ StackwalkerAMD64 walker(&system_info, &raw_context, &stack_region,
+ &local_modules, &frame_symbolizer);
+ vector<const CodeModule*> modules_without_symbols;
+ vector<const CodeModule*> modules_with_corrupt_symbols;
+ ASSERT_TRUE(walker.Walk(&call_stack, &modules_without_symbols,
+ &modules_with_corrupt_symbols));
+ ASSERT_EQ(0U, modules_without_symbols.size());
+ ASSERT_EQ(0U, modules_with_corrupt_symbols.size());
+ frames = call_stack.frames();
+
+ ASSERT_EQ(3U, frames->size());
+
+ { // To avoid reusing locals by mistake
+ StackFrameAMD64 *frame = static_cast<StackFrameAMD64 *>(frames->at(0));
+ EXPECT_EQ(StackFrame::FRAME_TRUST_CONTEXT, frame->trust);
+ ASSERT_EQ(StackFrameAMD64::CONTEXT_VALID_ALL, frame->context_validity);
+ EXPECT_EQ("", frame->function_name);
+ EXPECT_EQ(0x00000099a8150fd8ULL, frame->instruction);
+ EXPECT_EQ(0x00000099a8150fd8ULL, frame->context.rip);
+ EXPECT_EQ(frame0_rsp.Value(), frame->context.rsp);
+ EXPECT_EQ(frame0_rbp.Value(), frame->context.rbp);
+ }
+
+ { // To avoid reusing locals by mistake
+ StackFrameAMD64 *frame = static_cast<StackFrameAMD64 *>(frames->at(1));
+ EXPECT_EQ(StackFrame::FRAME_TRUST_SCAN, frame->trust);
+ ASSERT_EQ((StackFrameAMD64::CONTEXT_VALID_RIP |
+ StackFrameAMD64::CONTEXT_VALID_RSP |
+ StackFrameAMD64::CONTEXT_VALID_RBP),
+ frame->context_validity);
+ EXPECT_EQ("UserCallWinProcCheckWow", frame->function_name);
+ EXPECT_EQ(140710838468828ULL, frame->instruction + 1);
+ EXPECT_EQ(140710838468828ULL, frame->context.rip);
+ EXPECT_EQ(frame1_rsp.Value(), frame->context.rsp);
+ EXPECT_EQ(&user32_dll, frame->module);
+ }
+
+ { // To avoid reusing locals by mistake
+ StackFrameAMD64 *frame = static_cast<StackFrameAMD64 *>(frames->at(2));
+ EXPECT_EQ(StackFrame::FRAME_TRUST_CFI, frame->trust);
+ ASSERT_EQ((StackFrameAMD64::CONTEXT_VALID_RIP |
+ StackFrameAMD64::CONTEXT_VALID_RSP |
+ StackFrameAMD64::CONTEXT_VALID_RBP),
+ frame->context_validity);
+ EXPECT_EQ("DispatchMessageWorker", frame->function_name);
+ EXPECT_EQ(140710838467591ULL, frame->instruction + 1);
+ EXPECT_EQ(140710838467591ULL, frame->context.rip);
+ EXPECT_EQ(frame2_rsp.Value(), frame->context.rsp);
+ EXPECT_EQ(&user32_dll, frame->module);
+ }
+}
+
// Test that set_max_frames_scanned prevents using stack scanning
// to find caller frames.
TEST_F(GetCallerFrame, ScanningNotAllowed) {
generated by cgit v1.2.1 (git 2.18.0) at 2024-11-01 13:18:11 +0000