linker_memory: return success in enable_fallback_allocator.
Instead of aborting when in use, return a bool instead.
Test: debuggerd_test
Change-Id: Ifd2e4439303c95054298b0a05e0cb648ded1306c
diff --git a/linker/linker_memory.cpp b/linker/linker_memory.cpp
index 472c4e8..6a54c13 100644
--- a/linker/linker_memory.cpp
+++ b/linker/linker_memory.cpp
@@ -32,27 +32,28 @@
#include <sys/cdefs.h>
#include <unistd.h>
+#include <atomic>
+
#include <async_safe/log.h>
static LinkerMemoryAllocator g_linker_allocator;
-static pid_t fallback_tid = 0;
+static std::atomic<pid_t> fallback_tid(0);
// Used by libdebuggerd_handler to switch allocators during a crash dump, in
// case the linker heap is corrupted. Do not use this function.
-extern "C" void __linker_enable_fallback_allocator() {
- if (fallback_tid != 0) {
- async_safe_fatal("attempted to use currently-in-use fallback allocator");
- }
-
- fallback_tid = gettid();
+extern "C" bool __linker_enable_fallback_allocator() {
+ pid_t expected = 0;
+ return fallback_tid.compare_exchange_strong(expected, gettid());
}
extern "C" void __linker_disable_fallback_allocator() {
- if (fallback_tid == 0) {
+ pid_t previous = fallback_tid.exchange(0);
+ if (previous == 0) {
async_safe_fatal("attempted to disable unused fallback allocator");
+ } else if (previous != gettid()) {
+ async_safe_fatal("attempted to disable fallback allocator in use by another thread (%d)",
+ previous);
}
-
- fallback_tid = 0;
}
static LinkerMemoryAllocator& get_fallback_allocator() {