Implement LogLineLowStack() properly.
Avoid stack-based buffers used by the log formatting in
__android_log_print().
Move the VLOG(threads) in Thread::InitStackHwm() after the
low stack check as it's not safe to actually log before
that; even the StringPrintf() is using a stack-based buffer.
Bug: 18830897
Change-Id: I13b2166438e871c52ab91dabfe98f2200fd7c1cf
diff --git a/runtime/base/logging.cc b/runtime/base/logging.cc
index b781d60..7c2ef71 100644
--- a/runtime/base/logging.cc
+++ b/runtime/base/logging.cc
@@ -16,6 +16,7 @@
#include "logging.h"
+#include <limits>
#include <sstream>
#include "base/mutex.h"
@@ -239,8 +240,25 @@
void LogMessage::LogLineLowStack(const char* file, unsigned int line, LogSeverity log_severity,
const char* message) {
#ifdef HAVE_ANDROID_OS
- // TODO: be more conservative on stack usage here.
- LogLine(file, line, log_severity, message);
+ // Use android_writeLog() to avoid stack-based buffers used by android_printLog().
+ const char* tag = ProgramInvocationShortName();
+ int priority = kLogSeverityToAndroidLogPriority[log_severity];
+ char* buf = nullptr;
+ size_t buf_size = 0u;
+ if (priority == ANDROID_LOG_FATAL) {
+ // Allocate buffer for snprintf(buf, buf_size, "%s:%u] %s", file, line, message) below.
+ // If allocation fails, fall back to printing only the message.
+ buf_size = strlen(file) + 1 /* ':' */ + std::numeric_limits<typeof(line)>::max_digits10 +
+ 2 /* "] " */ + strlen(message) + 1 /* terminating 0 */;
+ buf = reinterpret_cast<char*>(malloc(buf_size));
+ }
+ if (buf != nullptr) {
+ snprintf(buf, buf_size, "%s:%u] %s", file, line, message);
+ android_writeLog(priority, tag, buf);
+ free(buf);
+ } else {
+ android_writeLog(priority, tag, message);
+ }
#else
static const char* log_characters = "VDIWEFF";
CHECK_EQ(strlen(log_characters), INTERNAL_FATAL + 1U);
diff --git a/runtime/thread.cc b/runtime/thread.cc
index 4a7103b..5ff7490 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -515,12 +515,6 @@
size_t read_guard_size;
GetThreadStack(tlsPtr_.pthread_self, &read_stack_base, &read_stack_size, &read_guard_size);
- // This is included in the SIGQUIT output, but it's useful here for thread debugging.
- VLOG(threads) << StringPrintf("Native stack is at %p (%s with %s guard)",
- read_stack_base,
- PrettySize(read_stack_size).c_str(),
- PrettySize(read_guard_size).c_str());
-
tlsPtr_.stack_begin = reinterpret_cast<uint8_t*>(read_stack_base);
tlsPtr_.stack_size = read_stack_size;
@@ -537,6 +531,12 @@
return false;
}
+ // This is included in the SIGQUIT output, but it's useful here for thread debugging.
+ VLOG(threads) << StringPrintf("Native stack is at %p (%s with %s guard)",
+ read_stack_base,
+ PrettySize(read_stack_size).c_str(),
+ PrettySize(read_guard_size).c_str());
+
// Set stack_end_ to the bottom of the stack saving space of stack overflows
Runtime* runtime = Runtime::Current();
