6.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Richter <tmricht@xxxxxxxxxxxxx>
[ Upstream commit e9f3af02f63909f41b43c28330434cc437639c5c ]
In case of a sampling event, the PAI PMU device drivers need a
reference to this event. Currently to PMU device driver reference
is removed when a sampling event is destroyed. This may lead to
situations where the reference of the PMU device driver is removed
while being used by a different sampling event.
Reset the event reference pointer of the PMU device driver when
a sampling event is deleted and before the next one might be added.
Fixes: 39d62336f5c1 ("s390/pai: add support for cryptography counters")
Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Acked-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/s390/kernel/perf_pai_crypto.c | 10 +++++++---
arch/s390/kernel/perf_pai_ext.c | 10 +++++++---
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index 522a5ea0a9f49..335e3f5d71f74 100644
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -90,7 +90,6 @@ static void paicrypt_event_destroy(struct perf_event *event)
event->cpu);
struct paicrypt_map *cpump = mp->mapptr;
- cpump->event = NULL;
static_branch_dec(&pai_key);
mutex_lock(&pai_reserve_mutex);
debug_sprintf_event(cfm_dbg, 5, "%s event %#llx cpu %d users %d"
@@ -348,10 +347,15 @@ static int paicrypt_add(struct perf_event *event, int flags)
static void paicrypt_stop(struct perf_event *event, int flags)
{
- if (!event->attr.sample_period) /* Counting */
+ struct paicrypt_mapptr *mp = this_cpu_ptr(paicrypt_root.mapptr);
+ struct paicrypt_map *cpump = mp->mapptr;
+
+ if (!event->attr.sample_period) { /* Counting */
paicrypt_read(event);
- else /* Sampling */
+ } else { /* Sampling */
perf_sched_cb_dec(event->pmu);
+ cpump->event = NULL;
+ }
event->hw.state = PERF_HES_STOPPED;
}
diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index 95d1a890640a3..db37c38ddcee4 100644
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -121,7 +121,6 @@ static void paiext_event_destroy(struct perf_event *event)
struct paiext_map *cpump = mp->mapptr;
mutex_lock(&paiext_reserve_mutex);
- cpump->event = NULL;
if (refcount_dec_and_test(&cpump->refcnt)) /* Last reference gone */
paiext_free(mp);
paiext_root_free();
@@ -355,10 +354,15 @@ static int paiext_add(struct perf_event *event, int flags)
static void paiext_stop(struct perf_event *event, int flags)
{
- if (!event->attr.sample_period) /* Counting */
+ struct paiext_mapptr *mp = this_cpu_ptr(paiext_root.mapptr);
+ struct paiext_map *cpump = mp->mapptr;
+
+ if (!event->attr.sample_period) { /* Counting */
paiext_read(event);
- else /* Sampling */
+ } else { /* Sampling */
perf_sched_cb_dec(event->pmu);
+ cpump->event = NULL;
+ }
event->hw.state = PERF_HES_STOPPED;
}
--
2.43.0
