Remove MAX_REGISTER_SIZE from py-unwind.c
Commit Message
> On 22 Jun 2017, at 10:08, Yao Qi <qiyaoltc@gmail.com> wrote:
>
> Alan Hayward <Alan.Hayward@arm.com> writes:
>
>> cached_frame
>> - = ((cached_frame_info *)
>> - xmalloc (sizeof (*cached_frame)
>> - + reg_count * sizeof (cached_frame->reg[0])));
>> + = ((cached_frame_info *) xmalloc (sizeof (*cached_frame)));
>
> Use XNEW, the code can be shorter,
>
>> @@ -601,6 +591,13 @@ static void
>> pyuw_dealloc_cache (struct frame_info *this_frame, void *cache)
>> {
>> TRACE_PY_UNWIND (3, "%s: enter", __FUNCTION__);
>> + cached_frame_info *cached_frame = (cached_frame_info *) cache;
>> +
>> + for (int i = 0; cached_frame->reg_count; i++)
>> + {
>> + xfree (cached_frame->reg[i].data);
>> + }
>
> No need to use braces.
>
> Otherwise, patch is good to me.
>
> --
> Yao (齐尧)
Ok, pushed with changes as suggested.
Patch below.
Thanks,
Alan.
Comments
On 06/22/2017 02:13 PM, Alan Hayward wrote:
> Ok, pushed with changes as suggested.
>
> Patch below.
Sorry, but this looks broken to me.
cached_frame_info is using the trailing array idiom ...
> @@ -93,7 +84,7 @@ typedef struct
> /* Length of the `reg' array below. */
> int reg_count;
>
> - struct reg_info reg[];
> + cached_reg_t reg[];
> } cached_frame_info;
>
>
> - cached_frame
> - = ((cached_frame_info *)
> - xmalloc (sizeof (*cached_frame)
> - + reg_count * sizeof (cached_frame->reg[0])));
> + cached_frame = XNEW (cached_frame_info);
but now you're not allocating enough space for the array elements...
> cached_frame->gdbarch = gdbarch;
> cached_frame->frame_id = unwind_info->frame_id;
> cached_frame->reg_count = reg_count;
> @@ -580,13 +568,14 @@ pyuw_sniffer (const struct frame_unwind *self, struct frame_info *this_frame,
> struct value *value = value_object_to_value (reg->value);
> size_t data_size = register_size (gdbarch, reg->number);
>
> - cached_frame->reg[i].number = reg->number;
> + cached_frame->reg[i].num = reg->number;
... that you're accessing here and below.
Valgrind probably shows the now-out-of-bounds accesses.
>
> /* `value' validation was done before, just assert. */
> gdb_assert (value != NULL);
> gdb_assert (data_size == TYPE_LENGTH (value_type (value)));
> gdb_assert (data_size <= MAX_REGISTER_SIZE);
>
> + cached_frame->reg[i].data = (gdb_byte *) xmalloc (data_size);
> memcpy (cached_frame->reg[i].data, value_contents (value), data_size);
> }
> }
> @@ -601,6 +590,11 @@ static void
> pyuw_dealloc_cache (struct frame_info *this_frame, void *cache)
> {
> TRACE_PY_UNWIND (3, "%s: enter", __FUNCTION__);
> + cached_frame_info *cached_frame = (cached_frame_info *) cache;
> +
> + for (int i = 0; cached_frame->reg_count; i++)
> + xfree (cached_frame->reg[i].data);
> +
> xfree (cache);
> }
>
@@ -73,15 +73,6 @@ typedef struct
/* The data we keep for a frame we can unwind: frame ID and an array of
(register_number, register_value) pairs. */
-struct reg_info
-{
- /* Register number. */
- int number;
-
- /* Register data bytes pointer. */
- gdb_byte data[MAX_REGISTER_SIZE];
-};
-
typedef struct
{
/* Frame ID. */
@@ -93,7 +84,7 @@ typedef struct
/* Length of the `reg' array below. */
int reg_count;
- struct reg_info reg[];
+ cached_reg_t reg[];
} cached_frame_info;
extern PyTypeObject pending_frame_object_type
@@ -483,14 +474,14 @@ pyuw_prev_register (struct frame_info *this_frame, void **cache_ptr,
int regnum)
{
cached_frame_info *cached_frame = (cached_frame_info *) *cache_ptr;
- struct reg_info *reg_info = cached_frame->reg;
- struct reg_info *reg_info_end = reg_info + cached_frame->reg_count;
+ cached_reg_t *reg_info = cached_frame->reg;
+ cached_reg_t *reg_info_end = reg_info + cached_frame->reg_count;
TRACE_PY_UNWIND (1, "%s (frame=%p,...,reg=%d)\n", __FUNCTION__, this_frame,
regnum);
for (; reg_info < reg_info_end; ++reg_info)
{
- if (regnum == reg_info->number)
+ if (regnum == reg_info->num)
return frame_unwind_got_bytes (this_frame, regnum, reg_info->data);
}
@@ -566,10 +557,7 @@ pyuw_sniffer (const struct frame_unwind *self, struct frame_info *this_frame,
saved_reg *reg;
int i;
- cached_frame
- = ((cached_frame_info *)
- xmalloc (sizeof (*cached_frame)
- + reg_count * sizeof (cached_frame->reg[0])));
+ cached_frame = XNEW (cached_frame_info);
cached_frame->gdbarch = gdbarch;
cached_frame->frame_id = unwind_info->frame_id;
cached_frame->reg_count = reg_count;
@@ -580,13 +568,14 @@ pyuw_sniffer (const struct frame_unwind *self, struct frame_info *this_frame,
struct value *value = value_object_to_value (reg->value);
size_t data_size = register_size (gdbarch, reg->number);
- cached_frame->reg[i].number = reg->number;
+ cached_frame->reg[i].num = reg->number;
/* `value' validation was done before, just assert. */
gdb_assert (value != NULL);
gdb_assert (data_size == TYPE_LENGTH (value_type (value)));
gdb_assert (data_size <= MAX_REGISTER_SIZE);
+ cached_frame->reg[i].data = (gdb_byte *) xmalloc (data_size);
memcpy (cached_frame->reg[i].data, value_contents (value), data_size);
}
}
@@ -601,6 +590,11 @@ static void
pyuw_dealloc_cache (struct frame_info *this_frame, void *cache)
{
TRACE_PY_UNWIND (3, "%s: enter", __FUNCTION__);
+ cached_frame_info *cached_frame = (cached_frame_info *) cache;
+
+ for (int i = 0; cached_frame->reg_count; i++)
+ xfree (cached_frame->reg[i].data);
+
xfree (cache);
}
@@ -232,6 +232,14 @@ enum regcache_dump_what
regcache_dump_remote
};
+/* A (register_number, register_value) pair. */
+
+typedef struct cached_reg
+{
+ int num;
+ gdb_byte *data;
+} cached_reg_t;
+
/* The register cache for storing raw register values. */
class regcache
@@ -6311,12 +6311,6 @@ remote_console_output (char *msg)
gdb_flush (gdb_stdtarg);
}
-typedef struct cached_reg
-{
- int num;
- gdb_byte *data;
-} cached_reg_t;
-
DEF_VEC_O(cached_reg_t);
typedef struct stop_reply