Change _stdio_handles_locking into _caller_handles_locking.
It is reported by tsan that funlockfile() can unlock an unlocked mutex.
It happens when printf() is called before fopen() or other stdio stuff.
As FLOCKFILE(fp) is called before __sinit(), _stdio_handles_locking is false,
and _FLOCK(fp) will not be locked. But then cantwrite(fp) in __vfprintf()
calls__sinit(), which makes _stdio_handles_locking become true, and
FUNLOCKFILE(fp) unlocks _FLOCK(fp).
Change _stdio_handles_locking into _caller_handles_locking,
so __sinit() won't change its value. Add test due to my previous fault.
Bug: 25392375
Change-Id: I483e3c3cdb28da65e62f1fd9615bf58c5403b4dd
diff --git a/libc/stdio/local.h b/libc/stdio/local.h
index ced94e3..3ae7059 100644
--- a/libc/stdio/local.h
+++ b/libc/stdio/local.h
@@ -109,7 +109,7 @@
pthread_mutex_t _lock;
/* __fsetlocking support */
- bool _stdio_handles_locking;
+ bool _caller_handles_locking;
};
#if defined(__cplusplus)
@@ -131,7 +131,7 @@
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); \
pthread_mutex_init(&_FLOCK(fp), &attr); \
pthread_mutexattr_destroy(&attr); \
- _EXT(fp)->_stdio_handles_locking = true; \
+ _EXT(fp)->_caller_handles_locking = false; \
} while (0)
#define _FILEEXT_SETUP(f, fext) \
@@ -208,8 +208,8 @@
(fp)->_lb._base = NULL; \
}
-#define FLOCKFILE(fp) if (_EXT(fp)->_stdio_handles_locking) flockfile(fp)
-#define FUNLOCKFILE(fp) if (_EXT(fp)->_stdio_handles_locking) funlockfile(fp)
+#define FLOCKFILE(fp) if (!_EXT(fp)->_caller_handles_locking) flockfile(fp)
+#define FUNLOCKFILE(fp) if (!_EXT(fp)->_caller_handles_locking) funlockfile(fp)
#define FLOATING_POINT
#define PRINTF_WIDE_CHAR