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[libbacktrace] Fix memory leak in loop in build_address_map 

When failing in build_address_map, we free the unit that's currently being
handled in the loop, but the ones that already have been allocated are leaked.

Fix this by keeping track of allocated units in a vector, and releasing them
upon failure.

Also, now that we have a vector of allocated units, move the freeing upon
failure of the abbrevs associated with each unit to build_address_map, and
remove the now redundant call to free_unit_addrs_vector.

Bootstrapped and reg-tested on x86_64.

2018-12-28  Ian Lance Taylor  <iant@golang.org>
	    Tom de Vries  <tdevries@suse.de>

	PR libbacktrace/88063
	* dwarf.c (free_unit_addrs_vector): Remove.
	(build_address_map): Keep track of allocated units in vector.  Free
	allocated units and corresponding abbrevs upon failure.  Remove now
	redundant call to free_unit_addrs_vector.  Free addrs vector upon
	failure.  Free allocated unit vector.

Co-Authored-By: Tom de Vries <tdevries@suse.de>

From-SVN: r267443
This commit is contained in:
Ian Lance Taylor 2018-12-28 03:43:26 +00:00 committed by Tom de Vries
parent 53a52133a5
commit 40b8d3b253
2 changed files with 44 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
libbacktrace/ChangeLog
View File

@ -1,3 +1,13 @@
2018-12-28 Ian Lance Taylor <iant@golang.org>
Tom de Vries <tdevries@suse.de>
PR libbacktrace/88063
* dwarf.c (free_unit_addrs_vector): Remove.
(build_address_map): Keep track of allocated units in vector. Free
allocated units and corresponding abbrevs upon failure. Remove now
redundant call to free_unit_addrs_vector. Free addrs vector upon
failure. Free allocated unit vector.
2018-12-28 Tom de Vries <tdevries@suse.de>
* dwarf.c (build_address_map): Free addrs vector upon failure.

60
libbacktrace/dwarf.c
View File

@ -923,21 +923,6 @@ add_unit_addr (struct backtrace_state *state, uintptr_t base_address,
return 1;
}
/* Free a unit address vector. */
static void
free_unit_addrs_vector (struct backtrace_state *state,
struct unit_addrs_vector *vec,
backtrace_error_callback error_callback, void *data)
{
struct unit_addrs *addrs;
size_t i;
addrs = (struct unit_addrs *) vec->vec.base;
for (i = 0; i < vec->count; ++i)
free_abbrevs (state, &addrs[i].u->abbrevs, error_callback, data);
}
/* Compare unit_addrs for qsort. When ranges are nested, make the
smallest one sort last. */
@ -1448,6 +1433,10 @@ build_address_map (struct backtrace_state *state, uintptr_t base_address,
{
struct dwarf_buf info;
struct abbrevs abbrevs;
struct backtrace_vector units;
size_t units_count;
size_t i;
struct unit **pu;
memset (&addrs->vec, 0, sizeof addrs->vec);
addrs->count = 0;
@ -1465,6 +1454,9 @@ build_address_map (struct backtrace_state *state, uintptr_t base_address,
info.data = data;
info.reported_underflow = 0;
memset (&units, 0, sizeof units);
units_count = 0;
memset (&abbrevs, 0, sizeof abbrevs);
while (info.left > 0)
{
@ -1503,10 +1495,20 @@ build_address_map (struct backtrace_state *state, uintptr_t base_address,
addrsize = read_byte (&unit_buf);
pu = ((struct unit **)
backtrace_vector_grow (state, sizeof (struct unit *),
error_callback, data, &units));
if (pu == NULL)
goto fail;
u = ((struct unit *)
backtrace_alloc (state, sizeof *u, error_callback, data));
if (u == NULL)
goto fail;
*pu = u;
++units_count;
u->unit_data = unit_buf.buf;
u->unit_data_len = unit_buf.left;
u->unit_data_offset = unit_buf.buf - unit_data_start;
@ -1531,27 +1533,33 @@ build_address_map (struct backtrace_state *state, uintptr_t base_address,
dwarf_ranges, dwarf_ranges_size,
is_bigendian, error_callback, data,
u, addrs))
{
free_abbrevs (state, &u->abbrevs, error_callback, data);
backtrace_free (state, u, sizeof *u, error_callback, data);
goto fail;
}
goto fail;
if (unit_buf.reported_underflow)
{
free_abbrevs (state, &u->abbrevs, error_callback, data);
backtrace_free (state, u, sizeof *u, error_callback, data);
goto fail;
}
goto fail;
}
if (info.reported_underflow)
goto fail;
// We only kept the list of units to free them on failure. On
// success the units are retained, pointed to by the entries in
// addrs.
backtrace_vector_free (state, &units, error_callback, data);
return 1;
fail:
if (units_count > 0)
{
pu = (struct unit **) units.base;
for (i = 0; i < units_count; i++)
{
free_abbrevs (state, &pu[i]->abbrevs, error_callback, data);
backtrace_free (state, pu[i], sizeof **pu, error_callback, data);
}
backtrace_vector_free (state, &units, error_callback, data);
}
free_abbrevs (state, &abbrevs, error_callback, data);
free_unit_addrs_vector (state, addrs, error_callback, data);
if (addrs->count > 0)
{
backtrace_vector_free (state, &addrs->vec, error_callback, data);