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From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, eranian@google.com, jolsa@redhat.com
Cc: linux-kernel@vger.kernel.org, tonyj@suse.com,
	nelson.dsouza@intel.com, peterz@infradead.org
Subject: [RFC][PATCH 8/8] perf/x86: Add sanity checks to x86_schedule_events()
Date: Thu, 14 Mar 2019 14:01:21 +0100	[thread overview]
Message-ID: <20190314130706.164351344@infradead.org> (raw)
In-Reply-To: 20190314130113.919278615@infradead.org


Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/events/core.c |   21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -855,17 +855,30 @@ int x86_schedule_events(struct cpu_hw_ev
 	struct event_constraint *c;
 	unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
 	struct perf_event *e;
-	int i, wmin, wmax, unsched = 0;
+	int n0, i, wmin, wmax, unsched = 0;
 	struct hw_perf_event *hwc;
 
 	bitmap_zero(used_mask, X86_PMC_IDX_MAX);
 
+	/*
+	 * Compute the number of events already present; see x86_pmu_add(),
+	 * validate_group() and x86_pmu_commit_txn(). For the former two
+	 * cpuc->n_events hasn't been updated yet, while for the latter
+	 * cpuc->n_txn contains the number of events added in the current
+	 * transaction.
+	 */
+	n0 = cpuc->n_events;
+	if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
+		n0 -= cpuc->n_txn;
+
 	if (x86_pmu.start_scheduling)
 		x86_pmu.start_scheduling(cpuc);
 
 	for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) {
 		c = cpuc->event_constraint[i];
 
+		WARN_ON_ONCE((c && i >= n0) || (!c && i < n0));
+
 		/*
 		 * Request constraints for new events; or for those events that
 		 * have a dynamic constraint due to the HT workaround -- for
@@ -945,11 +958,7 @@ int x86_schedule_events(struct cpu_hw_ev
 				x86_pmu.commit_scheduling(cpuc, i, assign[i]);
 		}
 	} else {
-		i = cpuc->n_events;
-		if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
-			i -= cpuc->n_txn;
-
-		for (; i < n; i++) {
+		for (i = n0; i < n; i++) {
 			e = cpuc->event_list[i];
 
 			/*



  parent reply	other threads:[~2019-03-14 13:11 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-14 13:01 [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Peter Zijlstra
2019-03-14 13:01 ` [PATCH 1/8] perf/x86/intel: Fix memory corruption Peter Zijlstra
2019-03-15 11:29   ` [tip:perf/urgent] " tip-bot for Peter Zijlstra
2019-03-19  6:29   ` [PATCH 1/8] " Stephane Eranian
2019-03-19 11:05     ` Peter Zijlstra
2019-03-19 17:52       ` Stephane Eranian
2019-03-19 18:20         ` Peter Zijlstra
2019-03-20 20:47           ` Stephane Eranian
2019-03-20 20:52             ` Stephane Eranian
2019-03-20 22:22             ` Peter Zijlstra
2019-03-21 12:38               ` Peter Zijlstra
2019-03-21 16:45                 ` Thomas Gleixner
2019-03-21 17:10                   ` Peter Zijlstra
2019-03-21 17:17                     ` Thomas Gleixner
2019-03-21 18:20                       ` Peter Zijlstra
2019-03-21 19:42                         ` Tony Jones
2019-03-21 19:47                           ` DSouza, Nelson
2019-03-21 20:07                             ` Peter Zijlstra
2019-03-21 23:16                               ` DSouza, Nelson
2019-03-22 22:14                                 ` DSouza, Nelson
2019-03-21 17:23                   ` Stephane Eranian
2019-03-21 17:51                     ` Thomas Gleixner
2019-03-22 19:04                       ` Stephane Eranian
2019-04-03  7:32                         ` Peter Zijlstra
2019-04-03 10:40                 ` [tip:perf/urgent] perf/x86/intel: Initialize TFA MSR tip-bot for Peter Zijlstra
2019-04-03 11:30                   ` Thomas Gleixner
2019-04-03 12:23                     ` Vince Weaver
2019-03-14 13:01 ` [RFC][PATCH 2/8] perf/x86/intel: Simplify intel_tfa_commit_scheduling() Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 3/8] perf/x86: Simplify x86_pmu.get_constraints() interface Peter Zijlstra
2019-03-19 21:21   ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 4/8] perf/x86: Remove PERF_X86_EVENT_COMMITTED Peter Zijlstra
2019-03-19 20:48   ` Stephane Eranian
2019-03-19 21:00     ` Peter Zijlstra
2019-03-20 13:14       ` Peter Zijlstra
2019-03-20 12:23     ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 5/8] perf/x86/intel: Optimize intel_get_excl_constraints() Peter Zijlstra
2019-03-19 23:43   ` Stephane Eranian
2019-03-14 13:01 ` [RFC][PATCH 6/8] perf/x86: Clear ->event_constraint[] on put Peter Zijlstra
2019-03-19 21:50   ` Stephane Eranian
2019-03-20 12:25     ` Peter Zijlstra
2019-03-14 13:01 ` [RFC][PATCH 7/8] perf/x86: Optimize x86_schedule_events() Peter Zijlstra
2019-03-19 23:55   ` Stephane Eranian
2019-03-20 13:11     ` Peter Zijlstra
2019-03-20 19:30       ` Stephane Eranian
2019-03-14 13:01 ` Peter Zijlstra [this message]
2019-03-15  7:15 ` [RFC][PATCH 0/8] perf/x86: event scheduling cleanups Stephane Eranian
2019-03-15  7:15   ` Stephane Eranian
2019-03-15  8:01     ` Peter Zijlstra

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