svn commit: r331324 - head/lib/libthr/thread

[John Baldwin]

Author: jhb
Date: Wed Mar 21 21:13:26 2018
New Revision: 331324
URL: https://svnweb.freebsd.org/changeset/base/331324

Log:
  Ensure thread library is initialized in pthread_testcancel().
  
  Call _thr_check_init() before reading curthread in pthread_testcancel().
  
  If a constructor in a library creates a semaphore via sem_init() and
  then waits for it via sem_wait(), the program can core dump in
  _pthread_testcancel() called from sem_wait().  This is because the
  semaphore implementation lives in libc, so the library's constructors
  can be run before libthr's constructors.
  
  Reported by:	arichardson
  Reviewed by:	kib
  Obtained from:	CheriBSD
  MFC after:	1 week
  Sponsored by:	DARPA / AFRL
  Differential Revision:	https://reviews.freebsd.org/D14786

Modified:
  head/lib/libthr/thread/thr_cancel.c

Modified: head/lib/libthr/thread/thr_cancel.c
==============================================================================
--- head/lib/libthr/thread/thr_cancel.c	Wed Mar 21 21:10:49 2018	(r331323)
+++ head/lib/libthr/thread/thr_cancel.c	Wed Mar 21 21:13:26 2018	(r331324)
@@ -132,8 +132,10 @@ _pthread_setcanceltype(int type, int *oldtype)
 void
 _pthread_testcancel(void)
 {
-	struct pthread *curthread = _get_curthread();
+	struct pthread *curthread;
 
+	_thr_check_init();
+	curthread = _get_curthread();
 	testcancel(curthread);
 }