From: Heather McIntyre <h...@rice.edu>
Signed-off-by: Heather S. McIntyre <h...@rice.edu>
Signed-off-by: Aaron Merey <ame...@redhat.com>
Signed-off-by: Mark Wielaard <m...@klomp.org>
---
v2 changes:
This replaces patch "libdw: Add locking around __libdw_dieabbrev for
dwarf_hasattr". Mark suggested that we remove lazy abbrev reading
in order to simplify the locking of __libdw_dieabbrev. This is
a fair bit of work so for now lets just put a write lock around all
of __libdw_dieabbrev. The removal of lazy reading of abbrev will be
done in a future patch.
libdw/dwarf_formref_die.c | 2 ++
libdw/dwarf_setalt.c | 4 ++++
libdw/libdwP.h | 23 +++++++++++++++++++----
3 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/libdw/dwarf_formref_die.c b/libdw/dwarf_formref_die.c
index 48ba8194..f8a51970 100644
--- a/libdw/dwarf_formref_die.c
+++ b/libdw/dwarf_formref_die.c
@@ -92,7 +92,9 @@ dwarf_formref_die (Dwarf_Attribute *attr, Dwarf_Die *result)
bool scan_debug_types = false;
do
{
+ rwlock_wrlock(attr->cu->dbg->dwarf_lock);
cu = __libdw_intern_next_unit (attr->cu->dbg, scan_debug_types);
+ rwlock_unlock(attr->cu->dbg->dwarf_lock);
if (cu == NULL)
{
if (scan_debug_types == false)
diff --git a/libdw/dwarf_setalt.c b/libdw/dwarf_setalt.c
index dc9b61cb..f7d70d9d 100644
--- a/libdw/dwarf_setalt.c
+++ b/libdw/dwarf_setalt.c
@@ -35,6 +35,8 @@
void
dwarf_setalt (Dwarf *main, Dwarf *alt)
{
+ rwlock_wrlock(main->dwarf_lock);
+
if (main->alt_fd != -1)
{
INTUSE(dwarf_end) (main->alt_dwarf);
@@ -43,5 +45,7 @@ dwarf_setalt (Dwarf *main, Dwarf *alt)
}
main->alt_dwarf = alt;
+
+ rwlock_unlock(main->dwarf_lock);
}
INTDEF (dwarf_setalt)
diff --git a/libdw/libdwP.h b/libdw/libdwP.h
index a4f26b82..9dce10e5 100644
--- a/libdw/libdwP.h
+++ b/libdw/libdwP.h
@@ -804,15 +804,28 @@ static inline Dwarf_Abbrev *
__nonnull_attribute__ (1)
__libdw_dieabbrev (Dwarf_Die *die, const unsigned char **readp)
{
+ if (unlikely (die->cu == NULL))
+ {
+ die->abbrev = DWARF_END_ABBREV;
+ return DWARF_END_ABBREV;
+ }
+
+ rwlock_wrlock (die->cu->abbrev_lock);
+
/* Do we need to get the abbreviation, or need to read after the code? */
if (die->abbrev == NULL || readp != NULL)
{
/* Get the abbreviation code. */
unsigned int code;
const unsigned char *addr = die->addr;
- if (unlikely (die->cu == NULL
- || addr >= (const unsigned char *) die->cu->endp))
- return die->abbrev = DWARF_END_ABBREV;
+
+ if (addr >= (const unsigned char *) die->cu->endp)
+ {
+ die->abbrev = DWARF_END_ABBREV;
+ rwlock_unlock (die->cu->abbrev_lock);
+ return DWARF_END_ABBREV;
+ }
+
get_uleb128 (code, addr, die->cu->endp);
if (readp != NULL)
*readp = addr;
@@ -821,7 +834,9 @@ __libdw_dieabbrev (Dwarf_Die *die, const unsigned char
**readp)
if (die->abbrev == NULL)
die->abbrev = __libdw_findabbrev (die->cu, code);
}
- return die->abbrev;
+
+ rwlock_unlock (die->cu->abbrev_lock);
+ return (Dwarf_Abbrev *) die->abbrev;
}
/* Helper functions for form handling. */
--
2.45.2
