Fix GC_scratch_alloc and GC_get_maps invocations to prevent SEGV

(if out of memory)

* dyn_load.c (GC_register_dynamic_libraries): If GC_scratch_alloc
fails (returns null) then abort (with the appropriate message) instead
of causing SEGV.
* os_dep.c (GC_dirty_init): Likewise.
* headers.c (GC_init_headers): Report error and exit if
GC_scratch_alloc fails.
* include/private/gc_priv.h (GC_scratch_alloc): Improve comment.
* os_dep.c (GC_print_address_map): If GC_get_maps return null then
print the appropriate message (instead of passing null to GC_err_puts
thus causing SEGV).

4 files changed, 13 insertions, 2 deletions

diff --git a/dyn_load.c b/dyn_load.c
index a543d9eb..39efc9b2 100644
--- a/dyn_load.c
+++ b/dyn_load.c
@@ -760,6 +760,8 @@ GC_INNER void GC_register_dynamic_libraries(void)
                         /* Expansion, plus room for 0 record */
         addr_map = (prmap_t *)GC_scratch_alloc(
                                 (word)current_sz * sizeof(prmap_t));
+        if (addr_map == NULL)
+          ABORT("Insufficient memory for address map");
     }
     if (ioctl(fd, PIOCMAP, addr_map) < 0) {
         GC_err_printf("fd = %d, errno = %d, needed_sz = %d, addr_map = %p\n",
diff --git a/headers.c b/headers.c
index de82c204..eac3e9f0 100644
--- a/headers.c
+++ b/headers.c
@@ -196,6 +196,10 @@ GC_INNER void GC_init_headers(void)
     register unsigned i;
 
     GC_all_nils = (bottom_index *)GC_scratch_alloc((word)sizeof(bottom_index));
+    if (GC_all_nils == NULL) {
+      GC_err_printf("Insufficient memory for GC_all_nils\n");
+      EXIT();
+    }
     BZERO(GC_all_nils, sizeof(bottom_index));
     for (i = 0; i < TOP_SZ; i++) {
         GC_top_index[i] = GC_all_nils;
diff --git a/include/private/gc_priv.h b/include/private/gc_priv.h
index 9d728a9a..b44347fe 100644
--- a/include/private/gc_priv.h
+++ b/include/private/gc_priv.h
@@ -1589,7 +1589,7 @@ GC_INNER void GC_unpromote_black_lists(void);
 GC_INNER ptr_t GC_scratch_alloc(size_t bytes);
                                 /* GC internal memory allocation for    */
                                 /* small objects.  Deallocation is not  */
-                                /* possible.                            */
+                                /* possible.  May return NULL.          */
 
 /* Heap block layout maps: */
 GC_INNER GC_bool GC_add_map_entry(size_t sz);
diff --git a/os_dep.c b/os_dep.c
index c1b7f209..333421d4 100644
--- a/os_dep.c
+++ b/os_dep.c
@@ -3641,6 +3641,8 @@ GC_INNER void GC_dirty_init(void)
 
     GC_dirty_maintained = TRUE;
     GC_proc_buf = GC_scratch_alloc(GC_proc_buf_size);
+    if (GC_proc_buf == NULL)
+      ABORT("Insufficient space for /proc read");
 }
 
 # define READ read
@@ -4724,8 +4726,11 @@ GC_INNER void GC_print_callers(struct callinfo info[NFRAMES])
   /* addresses in FIND_LEAK output.                                     */
   void GC_print_address_map(void)
   {
+    char *maps;
+
     GC_err_printf("---------- Begin address map ----------\n");
-    GC_err_puts(GC_get_maps());
+    maps = GC_get_maps();
+    GC_err_puts(maps != NULL ? maps : "Failed to get map!\n");
     GC_err_printf("---------- End address map ----------\n");
   }
 #endif /* LINUX && ELF */