fake_{loc,loclists,addr}_cu are Dwarf_CUs that are created separate from
all the others, so their contents are minimal and mostly initialized by
a calloc. On dwarf_end however, they are freed through the same code path
as all the others, so they call DAH_free like all the others. This changes
that so that these three are exempt from DAH and split-DWARF matters, and
swaps the calloc for a malloc so Memcheck will catch any others.
Signed-off-by: Jonathon Anderson <jm...@rice.edu>
---
> O! Sorry. I now see your original approach was actually correct. For
> some reason I believed the fake cus could have a split DWARF. But of
> course they never have. The reason I gave was wrong, but I still like
> this patch a little better because it more explicitly sets the needed
> values.
How about a bit of both, I'll be happy if I don't initialize `unit_type`.
Does this work?
> Could you add a Signed-off-by and ChangeLog entry?
Sure thing.
libdw/ChangeLog | 6 ++++++
libdw/dwarf_begin_elf.c | 18 +++++++++++++++---
libdw/dwarf_end.c | 23 ++++++++++++++---------
3 files changed, 35 insertions(+), 12 deletions(-)
diff --git a/libdw/ChangeLog b/libdw/ChangeLog
index 394c0df2..b1f73bc8 100644
--- a/libdw/ChangeLog
+++ b/libdw/ChangeLog
@@ -1,3 +1,9 @@
+2019-11-01 Jonathon Anderson <jm...@rice.edu>
+
+ * dwarf_begin_elf.c (valid_p): Switch calloc for malloc for fake CUs.
+ Add explicit initialization of some fields.
+ * dwarf_end.c (cu_free): Add clause to limit freeing of CU internals.
+
2019-08-26 Jonathon Anderson <jm...@rice.edu>
* libdw_alloc.c (__libdw_allocate): Added thread-safe stack allocator.
diff --git a/libdw/dwarf_begin_elf.c b/libdw/dwarf_begin_elf.c
index 8d137414..8c116847 100644
--- a/libdw/dwarf_begin_elf.c
+++ b/libdw/dwarf_begin_elf.c
@@ -223,7 +223,7 @@ valid_p (Dwarf *result)
inside the .debug_loc or .debug_loclists section. */
if (result != NULL && result->sectiondata[IDX_debug_loc] != NULL)
{
- result->fake_loc_cu = (Dwarf_CU *) calloc (1, sizeof (Dwarf_CU));
+ result->fake_loc_cu = (Dwarf_CU *) malloc (sizeof (Dwarf_CU));
if (unlikely (result->fake_loc_cu == NULL))
{
Dwarf_Sig8_Hash_free (&result->sig8_hash);
@@ -240,12 +240,16 @@ valid_p (Dwarf *result)
result->fake_loc_cu->endp
= (result->sectiondata[IDX_debug_loc]->d_buf
+ result->sectiondata[IDX_debug_loc]->d_size);
+ result->fake_loc_cu->locs = NULL;
+ result->fake_loc_cu->address_size = 0;
+ result->fake_loc_cu->version = 0;
+ result->fake_loc_cu->split = NULL;
}
}
if (result != NULL && result->sectiondata[IDX_debug_loclists] != NULL)
{
- result->fake_loclists_cu = (Dwarf_CU *) calloc (1, sizeof (Dwarf_CU));
+ result->fake_loclists_cu = (Dwarf_CU *) malloc (sizeof (Dwarf_CU));
if (unlikely (result->fake_loclists_cu == NULL))
{
Dwarf_Sig8_Hash_free (&result->sig8_hash);
@@ -263,6 +267,10 @@ valid_p (Dwarf *result)
result->fake_loclists_cu->endp
= (result->sectiondata[IDX_debug_loclists]->d_buf
+ result->sectiondata[IDX_debug_loclists]->d_size);
+ result->fake_loclists_cu->locs = NULL;
+ result->fake_loclists_cu->address_size = 0;
+ result->fake_loclists_cu->version = 0;
+ result->fake_loclists_cu->split = NULL;
}
}
@@ -272,7 +280,7 @@ valid_p (Dwarf *result)
inside the .debug_addr section, if it exists. */
if (result != NULL && result->sectiondata[IDX_debug_addr] != NULL)
{
- result->fake_addr_cu = (Dwarf_CU *) calloc (1, sizeof (Dwarf_CU));
+ result->fake_addr_cu = (Dwarf_CU *) malloc (sizeof (Dwarf_CU));
if (unlikely (result->fake_addr_cu == NULL))
{
Dwarf_Sig8_Hash_free (&result->sig8_hash);
@@ -291,6 +299,10 @@ valid_p (Dwarf *result)
result->fake_addr_cu->endp
= (result->sectiondata[IDX_debug_addr]->d_buf
+ result->sectiondata[IDX_debug_addr]->d_size);
+ result->fake_addr_cu->locs = NULL;
+ result->fake_addr_cu->address_size = 0;
+ result->fake_addr_cu->version = 0;
+ result->fake_addr_cu->split = NULL;
}
}
diff --git a/libdw/dwarf_end.c b/libdw/dwarf_end.c
index a2e94436..7e194a55 100644
--- a/libdw/dwarf_end.c
+++ b/libdw/dwarf_end.c
@@ -52,18 +52,23 @@ cu_free (void *arg)
{
struct Dwarf_CU *p = (struct Dwarf_CU *) arg;
- Dwarf_Abbrev_Hash_free (&p->abbrev_hash);
-
tdestroy (p->locs, noop_free);
- /* Free split dwarf one way (from skeleton to split). */
- if (p->unit_type == DW_UT_skeleton
- && p->split != NULL && p->split != (void *)-1)
+ /* Only free the CU internals if its not a fake CU. */
+ if(p != p->dbg->fake_loc_cu && p != p->dbg->fake_loclists_cu
+ && p != p->dbg->fake_addr_cu)
{
- /* The fake_addr_cu might be shared, only release one. */
- if (p->dbg->fake_addr_cu == p->split->dbg->fake_addr_cu)
- p->split->dbg->fake_addr_cu = NULL;
- INTUSE(dwarf_end) (p->split->dbg);
+ Dwarf_Abbrev_Hash_free (&p->abbrev_hash);
+
+ /* Free split dwarf one way (from skeleton to split). */
+ if (p->unit_type == DW_UT_skeleton
+ && p->split != NULL && p->split != (void *)-1)
+ {
+ /* The fake_addr_cu might be shared, only release one. */
+ if (p->dbg->fake_addr_cu == p->split->dbg->fake_addr_cu)
+ p->split->dbg->fake_addr_cu = NULL;
+ INTUSE(dwarf_end) (p->split->dbg);
+ }
}
}
--
2.24.0.rc2
