Only copy mcontext data from sigcontext.
The ucontext_t data structure could be bigger than the kernel data
structure. Since the unwinder only cares about the mcontext data, only
copy that out of the structure. The mcontext data is the same size in
the kernel and in the ucontext_t structure.
Bug: 15189014
Change-Id: I5978169c4425b8212e11db85a57eb319cd0e264b
diff --git a/libbacktrace/BacktraceThread.cpp b/libbacktrace/BacktraceThread.cpp
index 018d51f..b47cd2a 100644
--- a/libbacktrace/BacktraceThread.cpp
+++ b/libbacktrace/BacktraceThread.cpp
@@ -117,6 +117,12 @@
futex(&futex_, FUTEX_WAKE, INT_MAX, NULL, NULL, 0);
}
+void ThreadEntry::CopyUcontextFromSigcontext(void* sigcontext) {
+ ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(sigcontext);
+ // The only thing the unwinder cares about is the mcontext data.
+ memcpy(&ucontext_.uc_mcontext, &ucontext->uc_mcontext, sizeof(ucontext->uc_mcontext));
+}
+
//-------------------------------------------------------------------------
// BacktraceThread functions.
//-------------------------------------------------------------------------
@@ -129,7 +135,7 @@
return;
}
- entry->CopyUcontext(reinterpret_cast<ucontext_t*>(sigcontext));
+ entry->CopyUcontextFromSigcontext(sigcontext);
// Indicate the ucontext is now valid.
entry->Wake();
diff --git a/libbacktrace/BacktraceThread.h b/libbacktrace/BacktraceThread.h
index a75a807..ff3e9f3 100644
--- a/libbacktrace/BacktraceThread.h
+++ b/libbacktrace/BacktraceThread.h
@@ -40,14 +40,12 @@
static void Remove(ThreadEntry* entry);
- inline void CopyUcontext(ucontext_t* ucontext) {
- memcpy(&ucontext_, ucontext, sizeof(ucontext_));
- }
-
void Wake();
void Wait(int);
+ void CopyUcontextFromSigcontext(void*);
+
inline void Lock() {
pthread_mutex_lock(&mutex_);
// Reset the futex value in case of multiple unwinds of the same thread.