svn commit: r258767 - stable/9/lib/libthr/thread

[Konstantin Belousov]

Author: kib
Date: Sat Nov 30 14:39:56 2013
New Revision: 258767
URL: http://svnweb.freebsd.org/changeset/base/258767

Log:
  MFC r258499:
  Fix for the spurious signal handler call with zero signo in the threaded
  process.

Modified:
  stable/9/lib/libthr/thread/thr_private.h
  stable/9/lib/libthr/thread/thr_sig.c
Directory Properties:
  stable/9/lib/libthr/   (props changed)

Modified: stable/9/lib/libthr/thread/thr_private.h
==============================================================================
--- stable/9/lib/libthr/thread/thr_private.h	Sat Nov 30 14:36:32 2013	(r258766)
+++ stable/9/lib/libthr/thread/thr_private.h	Sat Nov 30 14:39:56 2013	(r258767)
@@ -431,6 +431,9 @@ struct pthread {
 	/* the sigaction should be used for deferred signal. */
 	struct sigaction	deferred_sigact;
 
+	/* deferred signal delivery is performed, do not reenter. */
+	int			deferred_run;
+
 	/* Force new thread to exit. */
 	int			force_exit;
 

Modified: stable/9/lib/libthr/thread/thr_sig.c
==============================================================================
--- stable/9/lib/libthr/thread/thr_sig.c	Sat Nov 30 14:36:32 2013	(r258766)
+++ stable/9/lib/libthr/thread/thr_sig.c	Sat Nov 30 14:39:56 2013	(r258767)
@@ -162,6 +162,7 @@ thr_sighandler(int sig, siginfo_t *info,
 	act = _thr_sigact[sig-1].sigact;
 	_thr_rwl_unlock(&_thr_sigact[sig-1].lock);
 	errno = err;
+	curthread->deferred_run = 0;
 
 	/*
 	 * if a thread is in critical region, for example it holds low level locks,
@@ -320,14 +321,18 @@ check_deferred_signal(struct pthread *cu
 	siginfo_t info;
 	int uc_len;
 
-	if (__predict_true(curthread->deferred_siginfo.si_signo == 0))
+	if (__predict_true(curthread->deferred_siginfo.si_signo == 0 ||
+	    curthread->deferred_run))
 		return;
 
+	curthread->deferred_run = 1;
 	uc_len = __getcontextx_size();
 	uc = alloca(uc_len);
 	getcontext(uc);
-	if (curthread->deferred_siginfo.si_signo == 0)
+	if (curthread->deferred_siginfo.si_signo == 0) {
+		curthread->deferred_run = 0;
 		return;
+	}
 	__fillcontextx2((char *)uc);
 	act = curthread->deferred_sigact;
 	uc->uc_sigmask = curthread->deferred_sigmask;