Commit e9f3af02 authored by Thomas Richter's avatar Thomas Richter Committed by Vasily Gorbik
Browse files

s390/pai: fix sampling event removal for PMU device driver 



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: 39d62336 ("s390/pai: add support for cryptography counters")
Signed-off-by: default avatarThomas Richter <tmricht@linux.ibm.com>
Acked-by: default avatarSumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent c9c26068

arch/s390/kernel/perf_pai_crypto.c

+7 −3
Original line number Diff line number Diff line
@@ -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"
@@ -356,10 +355,15 @@ 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;

}

arch/s390/kernel/perf_pai_ext.c

+7 −3
Original line number Diff line number Diff line
@@ -122,7 +122,6 @@ static void paiext_event_destroy(struct perf_event *event) 


	free_page(PAI_SAVE_AREA(event));

	mutex_lock(&paiext_reserve_mutex);

	cpump->event = NULL;

	if (refcount_dec_and_test(&cpump->refcnt))	/* Last reference gone */

		paiext_free(mp);

	paiext_root_free();
@@ -362,10 +361,15 @@ 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;

}