OS-5373 lx_proc panic while reading /proc/<pid>/exe link
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
OS-3820 lxbrand ptrace(2): the next generation
OS-3685 lxbrand PTRACE_O_TRACEFORK race condition
OS-3834 lxbrand 64-bit strace(1) reports 64-bit process as using x32 ABI
OS-3794 lxbrand panic on init signal death
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: Bryan Cantrill <bryan@joyent.com>

*** 19,29 ****
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
!  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
   */
  
  /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*        All Rights Reserved   */
  
--- 19,29 ----
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
!  * Copyright 2016, Joyent, Inc.
   */
  
  /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*        All Rights Reserved   */
  
*** 199,208 ****
--- 199,209 ----
                                  break;
                          case PR_SYSENTRY:
                          case PR_SYSEXIT:
                          case PR_SIGNALLED:
                          case PR_FAULTED:
+                         case PR_BRAND:
                                  /*
                                   * Make an lwp calling exit() be the
                                   * last lwp seen in the process.
                                   */
                                  if (t_istop == NULL ||
*** 532,541 ****
--- 533,548 ----
                          pcp->prc_datamodel = model;
                          pcp->prc_tid = tid;
                          pcp->prc_tslot = tslot;
                  }
          }
+ 
+         /*
+          * There may be threads waiting for the flag change blocked behind the
+          * pr_pid_cv as well.
+          */
+         cv_signal(&pr_pid_cv[p->p_slot]);
  }
  
  /*
   * Called from a hook in relvm() just before freeing the address space.
   * We free all the watched areas now.