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powerpc/papr_scm: Fix leaking nvdimm_events_map elements 

Right now 'char *' elements allocated for individual 'stat_id' in
'papr_scm_priv.nvdimm_events_map[]' during papr_scm_pmu_check_events(), get
leaked 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.

Fixes: 4c08d4bbc0 ("powerpc/papr_scm: Add perf interface support")
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220511082637.646714-1-vaibhav@linux.ibm.com
This commit is contained in:
Vaibhav Jain 2022-05-11 13:56:36 +05:30 committed by Michael Ellerman
parent fcee96924b
commit 0e0946e22f
1 changed files with 24 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
arch/powerpc/platforms/pseries/papr_scm.c
View File

@ -125,8 +125,8 @@ struct papr_scm_priv {
/* The bits which needs to be overridden */
u64 health_bitmap_inject_mask;
/* array to have event_code and stat_id mappings */
char **nvdimm_events_map;
/* array to have event_code and stat_id mappings */
u8 *nvdimm_events_map;
};
static int papr_scm_pmem_flush(struct nd_region *nd_region,
@ -370,7 +370,7 @@ static int papr_scm_pmu_get_value(struct perf_event *event, struct device *dev,
stat = &stats->scm_statistic[0];
memcpy(&stat->stat_id,
p->nvdimm_events_map[event->attr.config],
&p->nvdimm_events_map[event->attr.config * sizeof(stat->stat_id)],
sizeof(stat->stat_id));
stat->stat_val = 0;
@ -462,14 +462,13 @@ 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;
u32 available_events;
if (!p->stat_buffer_len)
return -ENOENT;
int index, rc = 0;
available_events = (p->stat_buffer_len - sizeof(struct papr_scm_perf_stats))
/ sizeof(struct papr_scm_perf_stat);
if (available_events == 0)
return -EOPNOTSUPP;
/* Allocate the buffer for phyp where stats are written */
stats = kzalloc(p->stat_buffer_len, GFP_KERNEL);
@ -478,35 +477,30 @@ 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;
goto out;
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;
}
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->stat_id),
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 * sizeof(stat->stat_id)],
&stat->stat_id, sizeof(stat->stat_id));
}
out:
kfree(stats);
return rc;
}