gold: ensure file_counts_lock is initialized before using

Since upgrading to binutils 2.35 I've been experiencing random memory
corruption related crashes with ld.gold --threads. It's caused by
multiple threads concurrently pushing elements onto the shared
std::vector in File_read::record_file_read(). This vector is supposed to
be protected by file_counts_lock, but that is initialized lazily and
might be NULL when File_read::open() is called, in which case
Hold_optional_lock silently skips locking it.

Fix by calling the initialize() method before attempting to acquire the
lock, the same as other places that use file_counts_lock.

	PR 26827
	* fileread.cc (File_read::open): Ensure file_counts_lock is
	initialized.
	* testsuite/Makefile.am (check_PROGRAMS): Add a test that passes
	-Wl,--threads.
	* testsuite/Makefile.in: Regenerate.

1 files changed, 1 insertions, 0 deletions

diff --git a/gold/fileread.cc b/gold/fileread.cc
index f5ca719360d..0b5228e2afd 100644
--- a/gold/fileread.cc
+++ b/gold/fileread.cc
@@ -212,6 +212,7 @@ File_read::open(const Task* task, const std::string& name)
       gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
 		 this->name_.c_str());
       this->token_.add_writer(task);
+      file_counts_initialize_lock.initialize();
       Hold_optional_lock hl(file_counts_lock);
       record_file_read(this->name_);
     }