libc: Add logcat error message for memory corruption
Our dlmalloc implementation currently calls abort() when it detects
that the heap is corrupted, or that an invalid pointer is passed to
one of its functions.
The only way to detect this is because abort() will force-fully
crash the current program with a magic fault address of '0xdeadbaad'.
However, this is not really well documented, and a frequent topic
on the android-ndk forum (among others).
This change makes our dlmalloc code dump a simple message to the
log just before the abort() call (and hence before the stack trace)
to better help identify the problem.
Change-Id: Iebf7eb7fe26463ecadfaca8f247d237edb441e3c
diff --git a/libc/bionic/dlmalloc.c b/libc/bionic/dlmalloc.c
index 19fbb75..035dbac 100644
--- a/libc/bionic/dlmalloc.c
+++ b/libc/bionic/dlmalloc.c
@@ -2265,13 +2265,53 @@
#else /* PROCEED_ON_ERROR */
-#ifndef CORRUPTION_ERROR_ACTION
-#define CORRUPTION_ERROR_ACTION(m) ABORT
-#endif /* CORRUPTION_ERROR_ACTION */
+/* The following Android-specific code is used to print an informative
+ * fatal error message to the log when we detect that a heap corruption
+ * was detected. We need to be careful about not using a log function
+ * that may require an allocation here!
+ */
+#ifdef __ANDROID__
-#ifndef USAGE_ERROR_ACTION
-#define USAGE_ERROR_ACTION(m,p) ABORT
-#endif /* USAGE_ERROR_ACTION */
+# include <private/logd.h>
+
+static void __bionic_heap_error(const char* msg, const char* function)
+{
+ /* We format the buffer explicitely, i.e. without using snprintf()
+ * which may use malloc() internally. Not something we can trust
+ * if we just detected a corrupted heap.
+ */
+ char buffer[256];
+ strlcpy(buffer, "@@@ ABORTING: ", sizeof(buffer));
+ strlcat(buffer, msg, sizeof(buffer));
+ if (function != NULL) {
+ strlcat(buffer, " IN ", sizeof(buffer));
+ strlcat(buffer, function, sizeof(buffer));
+ }
+ __libc_android_log_write(ANDROID_LOG_FATAL,"libc","%s", buffer);
+ abort();
+}
+
+# ifndef CORRUPTION_ERROR_ACTION
+# define CORRUPTION_ERROR_ACTION(m) \
+ __bionic_heap_error("HEAP MEMORY CORRUPTION", __FUNCTION__)
+# endif
+# ifndef USAGE_ERROR_ACTION
+# define USAGE_ERROR_ACTION(m,p) \
+ __bionic_heap_error("INVALID HEAP ADDRESS", __FUNCTION__)
+# endif
+
+#else /* !__ANDROID__ */
+
+# ifndef CORRUPTION_ERROR_ACTION
+# define CORRUPTION_ERROR_ACTION(m) ABORT
+# endif /* CORRUPTION_ERROR_ACTION */
+
+# ifndef USAGE_ERROR_ACTION
+# define USAGE_ERROR_ACTION(m,p) ABORT
+# endif /* USAGE_ERROR_ACTION */
+
+#endif /* !__ANDROID__ */
+
#endif /* PROCEED_ON_ERROR */