gdb/
	Fix occasional crash of CTRL-C during DWARF read in.
	* dwarf2read.c (dwarf2_mark_helper): Return on NULL CU.

gdb/ChangeLog

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index dffd058..60452ba 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2011-07-12  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	Fix occasional crash of CTRL-C during DWARF read in.
+	* dwarf2read.c (dwarf2_mark_helper): Return on NULL CU.
+
 2011-07-11  Tom Tromey  <tromey@redhat.com>
 
 	* regcache.c (struct regcache_descr): Fix typo.

gdb/dwarf2read.c

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index a5bf1f7..fde5b6a 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -15455,6 +15455,13 @@
   struct dwarf2_per_cu_data *per_cu;
 
   per_cu = (struct dwarf2_per_cu_data *) *slot;
+
+  /* cu->dependencies references may not yet have been ever read if QUIT aborts
+     reading of the chain.  As such dependencies remain valid it is not much
+     useful to track and undo them during QUIT cleanups.  */
+  if (per_cu->cu == NULL)
+    return 1;
+
   if (per_cu->cu->mark)
     return 1;
   per_cu->cu->mark = 1;