[PATCH 11/16] libdw: Add locking around __libdw_dieabbrev for dwarf_hasattr

[Mark Wielaard]

From: Heather McIntyre <hsm2@rice.edu>

	* libdw/dwarf_hasattr.c (dwarf_hasattr): Use die_abbrev_lock
	around __libdw_dieabbrev call.

Signed-off-by: Heather S. McIntyre <hsm2@rice.edu>
Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 libdw/dwarf_hasattr.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/libdw/dwarf_hasattr.c b/libdw/dwarf_hasattr.c
index eca08394..92f8de68 100644
--- a/libdw/dwarf_hasattr.c
+++ b/libdw/dwarf_hasattr.c
@@ -34,6 +34,10 @@
 #include <dwarf.h>
 #include "libdwP.h"
 
+/* dwarf_hasattr() calls __libdw_dieabbrev() in libdwP.h.
+   __libdw_dieabbrev() reads/writes "die->abbrev".
+   Mutual exclusion is enforced around the call to __libdw_dieabbrev to prevent a race. */
+rwlock_define(static, die_abbrev_lock);
 
 int
 dwarf_hasattr (Dwarf_Die *die, unsigned int search_name)
@@ -41,8 +45,13 @@ dwarf_hasattr (Dwarf_Die *die, unsigned int search_name)
   if (die == NULL)
     return 0;
 
+  rwlock_wrlock(die_abbrev_lock);
+
   /* Find the abbreviation entry.  */
   Dwarf_Abbrev *abbrevp = __libdw_dieabbrev (die, NULL);
+
+  rwlock_unlock(die_abbrev_lock);
+
   if (unlikely (abbrevp == DWARF_END_ABBREV))
     {
       __libdw_seterrno (DWARF_E_INVALID_DWARF);
-- 
2.41.0