6.6-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Richter tmricht@linux.ibm.com
[ 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@linux.ibm.com Acked-by: Sumanth Korikkar sumanthk@linux.ibm.com Signed-off-by: Vasily Gorbik gor@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 65cc74ab4cdd8..1eefbe2ff4189 100644 --- a/arch/s390/kernel/perf_pai_crypto.c +++ b/arch/s390/kernel/perf_pai_crypto.c @@ -53,7 +53,6 @@ static void paicrypt_event_destroy(struct perf_event *event) { struct paicrypt_map *cpump = per_cpu_ptr(&paicrypt_map, event->cpu);
- 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" @@ -278,10 +277,15 @@ 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 bac95261ec46d..a9235071ca70b 100644 --- a/arch/s390/kernel/perf_pai_ext.c +++ b/arch/s390/kernel/perf_pai_ext.c @@ -122,7 +122,6 @@ 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; }