Vaibhav Jain <vaib...@linux.ibm.com> writes:
> Right now 'char *' elements allocated individual 'stat_id' in
> 'papr_scm_priv.nvdimm_events_map' during papr_scm_pmu_check_events() leak in
> papr_scm_remove() and papr_scm_pmu_register(), papr_scm_pmu_check_events()
> error
> paths.
>
> Also individual 'stat_id' arent NULL terminated 'char *' instead they are
> fixed
> 8-byte sized identifiers. However papr_scm_pmu_register() assumes it to be a
> NULL terminated 'char *' and at other places it assumes it to be a
> 'papr_scm_perf_stat.stat_id' sized string which is 8-byes in size.
>
> Fix this by allocating the memory for papr_scm_priv.nvdimm_events_map to also
> include space for 'stat_id' entries. This is possible since number of
> available
> events/stat_ids are known upfront. This saves some memory and one extra level
> of
> indirection from 'nvdimm_events_map' to 'stat_id'. Also rest of the code
> can continue to call 'kfree(papr_scm_priv.nvdimm_events_map)' without needing
> to
> iterate over the array and free up individual elements.
>
> Also introduce a new typedef called 'state_id_t' thats a 'u8[8]' and can be
> used
> across papr_scm to deal with stat_ids.
>
> Fixes: 4c08d4bbc089 ("powerpc/papr_scm: Add perf interface support")
> Signed-off-by: Vaibhav Jain <vaib...@linux.ibm.com>
> ---
> arch/powerpc/platforms/pseries/papr_scm.c | 48 +++++++++++------------
> 1 file changed, 22 insertions(+), 26 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
> b/arch/powerpc/platforms/pseries/papr_scm.c
> index 39962c905542..f33a865ad5fb 100644
> --- a/arch/powerpc/platforms/pseries/papr_scm.c
> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> @@ -70,8 +70,10 @@
> #define PAPR_SCM_PERF_STATS_VERSION 0x1
>
> /* Struct holding a single performance metric */
> +typedef u8 stat_id_t[8];
> +
> struct papr_scm_perf_stat {
> - u8 stat_id[8];
> + stat_id_t stat_id;
> __be64 stat_val;
> } __packed;
Can we do this as two patch? One that fix the leak and other that adds
new type?
>
> @@ -126,7 +128,7 @@ struct papr_scm_priv {
> u64 health_bitmap_inject_mask;
>
> /* array to have event_code and stat_id mappings */
> - char **nvdimm_events_map;
> + stat_id_t *nvdimm_events_map;
> };
>
> static int papr_scm_pmem_flush(struct nd_region *nd_region,
> @@ -462,7 +464,7 @@ static int papr_scm_pmu_check_events(struct papr_scm_priv
> *p, struct nvdimm_pmu
> {
> struct papr_scm_perf_stat *stat;
> struct papr_scm_perf_stats *stats;
> - int index, rc, count;
> + int index, rc = 0;
> u32 available_events;
>
> if (!p->stat_buffer_len)
> @@ -478,35 +480,29 @@ static int papr_scm_pmu_check_events(struct
> papr_scm_priv *p, struct nvdimm_pmu
> return rc;
> }
>
> - /* Allocate memory to nvdimm_event_map */
> - p->nvdimm_events_map = kcalloc(available_events, sizeof(char *),
> GFP_KERNEL);
> - if (!p->nvdimm_events_map) {
> - rc = -ENOMEM;
> - goto out_stats;
> - }
> -
> /* Called to get list of events supported */
> rc = drc_pmem_query_stats(p, stats, 0);
> if (rc)
> - goto out_nvdimm_events_map;
> -
> - for (index = 0, stat = stats->scm_statistic, count = 0;
> - index < available_events; index++, ++stat) {
> - p->nvdimm_events_map[count] = kmemdup_nul(stat->stat_id, 8,
> GFP_KERNEL);
> - if (!p->nvdimm_events_map[count]) {
> - rc = -ENOMEM;
> - goto out_nvdimm_events_map;
> - }
> + goto out;
>
> - count++;
> + /*
> + * Allocate memory and populate nvdimm_event_map.
> + * Allocate an extra element for NULL entry
> + */
> + p->nvdimm_events_map = kcalloc(available_events + 1,
> + sizeof(stat_id_t), GFP_KERNEL);
> + if (!p->nvdimm_events_map) {
> + rc = -ENOMEM;
> + goto out;
> }
> - p->nvdimm_events_map[count] = NULL;
> - kfree(stats);
> - return 0;
>
> -out_nvdimm_events_map:
> - kfree(p->nvdimm_events_map);
> -out_stats:
> + /* Copy all stat_ids to event map */
> + for (index = 0, stat = stats->scm_statistic;
> + index < available_events; index++, ++stat) {
> + memcpy(&p->nvdimm_events_map[index], &stat->stat_id,
> + sizeof(stat_id_t));
> + }
> +out:
> kfree(stats);
> return rc;
> }
>
> base-commit: 348c71344111d7a48892e3e52264ff11956fc196
> --
> 2.35.1
