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From:   Ravi Bangoria <ravi.bangoria@amd.com>
To:     <peterz@infradead.org>
CC:     <ravi.bangoria@amd.com>, <mingo@redhat.com>, <acme@kernel.org>,
        <mark.rutland@arm.com>, <jolsa@redhat.com>, <namhyung@kernel.org>,
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        <linux-kernel@vger.kernel.org>, <sandipan.das@amd.com>,
        <ananth.narayan@amd.com>, <santosh.shukla@amd.com>
Subject: [PATCH] perf/core: Don't allow grouping events from different hw pmus
Date:   Tue, 22 Nov 2022 13:33:26 +0530
Message-ID: <20221122080326.228-1-ravi.bangoria@amd.com>
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Event group from different hw pmus does not make sense and thus perf
has never allowed it. However, with recent rewrite that restriction
has been inadvertently removed. Fix it.

Fixes: bd2756811766 ("perf: Rewrite core context handling")
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
---
 kernel/events/core.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 5f262f91cd31..4ee866ef075d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -12499,15 +12499,21 @@ SYSCALL_DEFINE5(perf_event_open,
 			 * perf_event_pmu_context.
 			 */
 			pmu = group_leader->pmu_ctx->pmu;
-		} else if (!is_software_event(event) &&
-			is_software_event(group_leader) &&
-			(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
-			/*
-			 * In case the group is a pure software group, and we
-			 * try to add a hardware event, move the whole group to
-			 * the hardware context.
-			 */
-			move_group = 1;
+		} else if (!is_software_event(event)) {
+			if (is_software_event(group_leader) &&
+			    (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
+				/*
+				 * In case the group is a pure software group, and we
+				 * try to add a hardware event, move the whole group to
+				 * the hardware context.
+				 */
+				move_group = 1;
+			}
+
+			/* Don't allow group of multiple hw events from different pmus */
+			if (!in_software_context(group_leader) &&
+			    group_leader->pmu_ctx->pmu != pmu)
+				goto err_locked;
 		}
 	}
 
-- 
2.38.1