Add a new unwind method on error.
If a function crashes by jumping into unexecutable code, the old method
could not unwind through that. Add a fallback method to set the pc from
the default return address location.
In addition, add a new finished check for steps. This will provide a method
to indicate that this step is the last step. This prevents cases where
the fallback method might be triggered incorrectly.
Update the libbacktrace code to unwind using the new methodology.
Update the unwind tool to use the new unwind methodology.
Add a new option to crasher that calls through a null function.
Create a new object, Unwinder, that encapsulates the a basic unwind. For now,
libbacktrace will still use the custom code.
Added new unit tests to cover the new cases. Also add a test that
crashes calling a nullptr as a function, and then has call frames in
the signal stack.
Bug: 65842173
Test: Pass all unit tests, verify crasher dumps properly.
Change-Id: Ia18430ab107e9f7bdf0e14a9b74710b1280bd7f4
diff --git a/debuggerd/crasher/crasher.cpp b/debuggerd/crasher/crasher.cpp
index f57349b..e9a3ebd 100644
--- a/debuggerd/crasher/crasher.cpp
+++ b/debuggerd/crasher/crasher.cpp
@@ -114,6 +114,11 @@
return reinterpret_cast<uintptr_t>(result);
}
+noinline int crash_null() {
+ int (*null_func)() = nullptr;
+ return null_func();
+}
+
noinline int crash3(int a) {
*reinterpret_cast<int*>(0xdead) = a;
return a*4;
@@ -169,6 +174,7 @@
fprintf(stderr, " nostack crash with a NULL stack pointer\n");
fprintf(stderr, "\n");
fprintf(stderr, " heap-usage cause a libc abort by abusing a heap function\n");
+ fprintf(stderr, " call-null cause a crash by calling through a nullptr\n");
fprintf(stderr, " leak leak memory until we get OOM-killed\n");
fprintf(stderr, "\n");
fprintf(stderr, " abort call abort()\n");
@@ -239,6 +245,8 @@
crashnostack();
} else if (!strcasecmp(arg, "exit")) {
exit(1);
+ } else if (!strcasecmp(arg, "call-null")) {
+ return crash_null();
} else if (!strcasecmp(arg, "crash") || !strcmp(arg, "SIGSEGV")) {
return crash(42);
} else if (!strcasecmp(arg, "abort")) {