diff options
Diffstat (limited to 'src/processor/stackwalker_x86.cc')
| -rw-r--r-- | src/processor/stackwalker_x86.cc | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/src/processor/stackwalker_x86.cc b/src/processor/stackwalker_x86.cc index 29d98e4b..ed2b383d 100644 --- a/src/processor/stackwalker_x86.cc +++ b/src/processor/stackwalker_x86.cc @@ -200,13 +200,15 @@ StackFrameX86* StackwalkerX86::GetCallerByWindowsFrameInfo( } } - // Set up the dictionary for the PostfixEvaluator. %ebp and %esp are used - // in each program string, and their previous values are known, so set them - // here. + // Set up the dictionary for the PostfixEvaluator. %ebp, %esp, and sometimes + // %ebx are used in program strings, and their previous values are known, so + // set them here. PostfixEvaluator<uint32_t>::DictionaryType dictionary; // Provide the current register values. dictionary["$ebp"] = last_frame->context.ebp; dictionary["$esp"] = last_frame->context.esp; + if (last_frame->context_validity & StackFrameX86::CONTEXT_VALID_EBX) + dictionary["$ebx"] = last_frame->context.ebx; // Provide constants from the debug info for last_frame and its callee. // .cbCalleeParams is a Breakpad extension that allows us to use the // PostfixEvaluator engine when certain types of debugging information @@ -330,11 +332,19 @@ StackFrameX86* StackwalkerX86::GetCallerByWindowsFrameInfo( // evaluation. The stack will not be examined to locate a saved // %ebp value, because these frames do not save (or use) %ebp. // + // We also propagate %ebx through, as it is commonly unmodifed after + // calling simple forwarding functions in ntdll (that are this non-EBP + // using type). It's not clear that this is always correct, but it is + // important for some functions to get a correct walk. + // // %eip_new = *(%esp_old + callee_params + saved_regs + locals) // %esp_new = %esp_old + callee_params + saved_regs + locals + 4 // %ebp_new = %ebp_old + // %ebx_new = %ebx_old // If available. program_string = "$eip .raSearchStart ^ = " - "$esp .raSearchStart 4 + ="; + "$esp .raSearchStart 4 + ="; + if (last_frame->context_validity & StackFrameX86::CONTEXT_VALID_EBX) + program_string += " $ebx $ebx ="; recover_ebp = false; } @@ -649,15 +659,13 @@ StackFrame* StackwalkerX86::GetCallerFrame(const CallStack* stack, if (!new_frame.get()) return NULL; - // Treat an instruction address of 0 as end-of-stack. - if (new_frame->context.eip == 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.esp <= last_frame->context.esp) + // Should we terminate the stack walk? (end-of-stack or broken invariant) + if (TerminateWalk(new_frame->context.eip, + new_frame->context.esp, + last_frame->context.esp, + frames.size() == 1)) { return NULL; + } // new_frame->context.eip is the return address, which is the instruction // after the CALL that caused us to arrive at the callee. Set |