On Wed, Apr 05, 2023 at 04:44:10PM +0100, Bruce Richardson wrote:
> On Alpine linux, the telemetry_data_autotest was failing for the
> test where we had dictionaries embedded in other dictionaries up
> to three levels deep. Indications are that this issue is due to
> excess data being stored on the stack, so replace stack-allocated
> buffer data with dynamically allocated data in the case where we
> are doing recursive processing of telemetry data structures into
> json.
>
> Bugzilla ID: 1177
> Fixes: c933bb5177ca ("telemetry: support array values in data object")
> Fixes: d2671e642a8e ("telemetry: support dict of dicts")
> Cc: sta...@dpdk.org
>
> Signed-off-by: Bruce Richardson <bruce.richard...@intel.com>
>
> ---
Acked-by: Tyler Retzlaff <roret...@linux.microsoft.com>
(one observation below)
> V2:
> set '\0' in newly malloc'ed buffer to ensure it always has valid
> string data.
> ---
> lib/telemetry/telemetry.c | 21 ++++++++++++++++++---
> 1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/lib/telemetry/telemetry.c b/lib/telemetry/telemetry.c
> index 7bceadcee7..728a0bffd4 100644
> --- a/lib/telemetry/telemetry.c
> +++ b/lib/telemetry/telemetry.c
> @@ -208,7 +208,11 @@ container_to_json(const struct rte_tel_data *d, char
> *out_buf, size_t buf_len)
> break;
> case RTE_TEL_CONTAINER:
> {
> - char temp[buf_len];
> + char *temp = malloc(buf_len);
> + if (temp == NULL)
> + break;
> + *temp = '\0'; /* ensure valid string */
> +
> const struct container *cont =
> &v->value.container;
> if (container_to_json(cont->data,
> @@ -219,6 +223,7 @@ container_to_json(const struct rte_tel_data *d, char
> *out_buf, size_t buf_len)
> v->name, temp);
> if (!cont->keep)
> rte_tel_data_free(cont->data);
> + free(temp);
> break;
> }
> }
> @@ -275,7 +280,11 @@ output_json(const char *cmd, const struct rte_tel_data
> *d, int s)
> break;
> case RTE_TEL_CONTAINER:
> {
> - char temp[buf_len];
> + char *temp = malloc(buf_len);
> + if (temp == NULL)
> + break;
> + *temp = '\0'; /* ensure valid string */
> +
> const struct container *cont =
> &v->value.container;
> if (container_to_json(cont->data,
> @@ -286,6 +295,7 @@ output_json(const char *cmd, const struct rte_tel_data
> *d, int s)
> v->name, temp);
> if (!cont->keep)
> rte_tel_data_free(cont->data);
> + free(temp);
not expressing a preference just noticing that when
RTE_TEL_CONTAINER cases are the last case in the switch sometimes there
is an explicit break; and sometimes not.
> }
> }
> }
> @@ -311,7 +321,11 @@ output_json(const char *cmd, const struct rte_tel_data
> *d, int s)
> buf_len, used,
> d->data.array[i].uval);
> else if (d->type == TEL_ARRAY_CONTAINER) {
> - char temp[buf_len];
> + char *temp = malloc(buf_len);
> + if (temp == NULL)
> + break;
> + *temp = '\0'; /* ensure valid string */
> +
> const struct container *rec_data =
> &d->data.array[i].container;
> if (container_to_json(rec_data->data,
> @@ -321,6 +335,7 @@ output_json(const char *cmd, const struct rte_tel_data
> *d, int s)
> buf_len, used, temp);
> if (!rec_data->keep)
> rte_tel_data_free(rec_data->data);
> + free(temp);
> }
> break;
> }
> --
> 2.37.2
