svn commit: r324671 - head/sys/kern

[Konstantin Belousov]

Author: kib
Date: Mon Oct 16 20:21:51 2017
New Revision: 324671
URL: https://svnweb.freebsd.org/changeset/base/324671

Log:
  Re-evaluate thread' signal mask after ptracestop().
  
  The stop drops process lock, which allows the signal mask to be
  changed and our selected signal might become blocked, i.e. should be
  returned to the process queue instead of delivery.
  
  Also, for the existing check of the process no longer having an
  attached debugger, we should not loose the signal, but requeue it.
  
  Reported and tested by:	bdrewery
  Reviewed by:	jhb
  Sponsored by:	The FreeBSD Foundation
  MFC after:	1 week

Modified:
  head/sys/kern/kern_sig.c

Modified: head/sys/kern/kern_sig.c
==============================================================================
--- head/sys/kern/kern_sig.c	Mon Oct 16 20:15:19 2017	(r324670)
+++ head/sys/kern/kern_sig.c	Mon Oct 16 20:21:51 2017	(r324671)
@@ -2855,15 +2855,32 @@ issignal(struct thread *td)
 			mtx_lock(&ps->ps_mtx);
 
 			/* 
-			 * Keep looking if the debugger discarded the signal
-			 * or replaced it with a masked signal.
-			 *
-			 * If the traced bit got turned off, go back up
-			 * to the top to rescan signals.  This ensures
-			 * that p_sig* and p_sigact are consistent.
+			 * Keep looking if the debugger discarded or
+			 * replaced the signal.
 			 */
-			if (sig == 0 || (p->p_flag & P_TRACED) == 0)
+			if (sig == 0)
 				continue;
+
+			/*
+			 * If the signal became masked, re-queue it.
+			 */
+			if (SIGISMEMBER(td->td_sigmask, sig)) {
+				ksi.ksi_flags |= KSI_HEAD;
+				sigqueue_add(&p->p_sigqueue, sig, &ksi);
+				continue;
+			}
+
+			/*
+			 * If the traced bit got turned off, requeue
+			 * the signal and go back up to the top to
+			 * rescan signals.  This ensures that p_sig*
+			 * and p_sigact are consistent.
+			 */
+			if ((p->p_flag & P_TRACED) == 0) {
+				ksi.ksi_flags |= KSI_HEAD;
+				sigqueue_add(queue, sig, &ksi);
+				continue;
+			}
 		}
 
 		prop = sigprop(sig);