3830 SIGQUEUE_MAX's limit of 32 is too low
Reviewed by: Cedric Blancher <cedric.blancher@gmail.com>
Reviewed by: John Kennedy <john.kennedy@delphix.com>
Reviewed by: Irek Szczesniak <iszczesniak@gmail.com>

*** 2369,2403 ****
                  }
          }
          return (0);
  }
  
- #ifndef UCHAR_MAX
- #define UCHAR_MAX       255
- #endif
- 
  /*
!  * The entire pool (with maxcount entries) is pre-allocated at
!  * the first sigqueue/signotify call.
   */
  sigqhdr_t *
  sigqhdralloc(size_t size, uint_t maxcount)
  {
          size_t i;
          sigqueue_t *sq, *next;
          sigqhdr_t *sqh;
  
!         i = (maxcount * size) + sizeof (sigqhdr_t);
!         ASSERT(maxcount <= UCHAR_MAX && i <= USHRT_MAX);
          sqh = kmem_alloc(i, KM_SLEEP);
!         sqh->sqb_count = (uchar_t)maxcount;
!         sqh->sqb_maxcount = (uchar_t)maxcount;
!         sqh->sqb_size = (ushort_t)i;
          sqh->sqb_pexited = 0;
          sqh->sqb_sent = 0;
          sqh->sqb_free = sq = (sigqueue_t *)(sqh + 1);
!         for (i = maxcount - 1; i != 0; i--) {
                  next = (sigqueue_t *)((uintptr_t)sq + size);
                  sq->sq_next = next;
                  sq = next;
          }
          sq->sq_next = NULL;
--- 2369,2405 ----
                  }
          }
          return (0);
  }
  
  /*
!  * The pre-allocated pool (with _SIGQUEUE_PREALLOC entries) is
!  * allocated at the first sigqueue/signotify call.
   */
  sigqhdr_t *
  sigqhdralloc(size_t size, uint_t maxcount)
  {
          size_t i;
          sigqueue_t *sq, *next;
          sigqhdr_t *sqh;
  
!         /*
!          * Before the introduction of process.max-sigqueue-size
!          * _SC_SIGQUEUE_MAX had this static value.
!          */
! #define _SIGQUEUE_PREALLOC      32
! 
!         i = (_SIGQUEUE_PREALLOC * size) + sizeof (sigqhdr_t);
!         ASSERT(maxcount <= INT_MAX);
          sqh = kmem_alloc(i, KM_SLEEP);
!         sqh->sqb_count = maxcount;
!         sqh->sqb_maxcount = maxcount;
!         sqh->sqb_size = i;
          sqh->sqb_pexited = 0;
          sqh->sqb_sent = 0;
          sqh->sqb_free = sq = (sigqueue_t *)(sqh + 1);
!         for (i = _SIGQUEUE_PREALLOC - 1; i != 0; i--) {
                  next = (sigqueue_t *)((uintptr_t)sq + size);
                  sq->sq_next = next;
                  sq = next;
          }
          sq->sq_next = NULL;
*** 2407,2418 ****
  }
  
  static void sigqrel(sigqueue_t *);
  
  /*
!  * allocate a sigqueue/signotify structure from the per process
!  * pre-allocated pool.
   */
  sigqueue_t *
  sigqalloc(sigqhdr_t *sqh)
  {
          sigqueue_t *sq = NULL;
--- 2409,2421 ----
  }
  
  static void sigqrel(sigqueue_t *);
  
  /*
!  * Allocate a sigqueue/signotify structure from the per process
!  * pre-allocated pool or allocate a new sigqueue/signotify structure
!  * if the pre-allocated pool is exhausted.
   */
  sigqueue_t *
  sigqalloc(sigqhdr_t *sqh)
  {
          sigqueue_t *sq = NULL;
*** 2421,2436 ****
  
          if (sqh != NULL) {
                  mutex_enter(&sqh->sqb_lock);
                  if (sqh->sqb_count > 0) {
                          sqh->sqb_count--;
                          sq = sqh->sqb_free;
                          sqh->sqb_free = sq->sq_next;
                          mutex_exit(&sqh->sqb_lock);
                          bzero(&sq->sq_info, sizeof (k_siginfo_t));
                          sq->sq_backptr = sqh;
-                         sq->sq_func = sigqrel;
                          sq->sq_next = NULL;
                          sq->sq_external = 0;
                  } else {
                          mutex_exit(&sqh->sqb_lock);
                  }
--- 2424,2447 ----
  
          if (sqh != NULL) {
                  mutex_enter(&sqh->sqb_lock);
                  if (sqh->sqb_count > 0) {
                          sqh->sqb_count--;
+                         if (sqh->sqb_free == NULL) {
+                                 /*
+                                  * The pre-allocated pool is exhausted.
+                                  */
+                                 sq = kmem_alloc(sizeof (sigqueue_t), KM_SLEEP);
+                                 sq->sq_func = NULL;
+                         } else {
                                  sq = sqh->sqb_free;
+                                 sq->sq_func = sigqrel;
                                  sqh->sqb_free = sq->sq_next;
+                         }
                          mutex_exit(&sqh->sqb_lock);
                          bzero(&sq->sq_info, sizeof (k_siginfo_t));
                          sq->sq_backptr = sqh;
                          sq->sq_next = NULL;
                          sq->sq_external = 0;
                  } else {
                          mutex_exit(&sqh->sqb_lock);
                  }