Subject: FAILED: patch "[PATCH] perf/x86/intel: Fix GRT PEBS load/store direction for latency" failed to apply to 6.18-stable tree
To: dapeng1.mi@linux.intel.com,mingo@kernel.org,peterz@infradead.org,stable@vger.kernel.org
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Tue, 29 Sep 2026 13:35:19 +0200
Message-ID: <2026092919-dab-circus-267e@gregkh>
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The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 89dc568e8c0be60e05e5fcd0b528c79077d7b84b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026092919-dab-circus-267e@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 89dc568e8c0be60e05e5fcd0b528c79077d7b84b Mon Sep 17 00:00:00 2001
From: Dapeng Mi <dapeng1.mi@linux.intel.com>
Date: Thu, 17 Sep 2026 09:52:23 +0800
Subject: [PATCH] perf/x86/intel: Fix GRT PEBS load/store direction for latency
 events, to fix sample classification

On Gracemont, intel_grt_pebs_event_constraints[] applies LAT_CONSTRAINT
constraints to MEM_UOPS_RETIRED.{LOAD,STORE}_LATENCY, but does not set
explicit LOAD/STORE flags for those events.

The PEBS latency path (pebs_latency_data(), via __grt_latency_data())
uses the event flags to determine memory operation direction. Without an
explicit STORE flag, samples from MEM_UOPS_RETIRED.STORE_LATENCY can be
misclassified as LOADs.

Set explicit LOAD/STORE flags in intel_grt_pebs_event_constraints[] for:

- MEM_UOPS_RETIRED.LOAD_LATENCY
- MEM_UOPS_RETIRED.STORE_LATENCY

Also update __grt_latency_data() to explicitly interpret these flags when
assigning the sampled memory operation direction.

This fixes incorrect STORE sample classification.

Fixes: 39a41278f041 ("perf/x86/intel: Fix PEBS memory access info encoding for ADL")
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: <stable@vger.kernel.org> # v7.2+
Link: https://patch.msgid.link/20260917015234.981153-2-dapeng1.mi@linux.intel.com

diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
index b98029b44052..fff98f457576 100644
--- a/arch/x86/events/intel/ds.c
+++ b/arch/x86/events/intel/ds.c
@@ -455,6 +455,7 @@ static inline void pebs_set_tlb_lock(u64 *val, bool tlb, bool lock)
 static u64 __grt_latency_data(struct perf_event *event, u64 status,
 			       u8 dse, bool tlb, bool lock, bool blk)
 {
+	union perf_mem_data_src src;
 	u64 val;
 
 	WARN_ON_ONCE(is_hybrid() &&
@@ -470,7 +471,16 @@ static u64 __grt_latency_data(struct perf_event *event, u64 status,
 	else
 		val |= P(BLK, NA);
 
-	return val;
+	src.val = val;
+
+	if (event->hw.flags &
+	    (PERF_X86_EVENT_PEBS_LDLAT | PERF_X86_EVENT_PEBS_LD_HSW))
+		src.mem_op = P(OP, LOAD);
+	if (event->hw.flags &
+	    (PERF_X86_EVENT_PEBS_STLAT | PERF_X86_EVENT_PEBS_ST_HSW))
+		src.mem_op = P(OP, STORE);
+
+	return src.val;
 }
 
 u64 grt_latency_data(struct perf_event *event, u64 status)
@@ -1291,8 +1301,8 @@ struct event_constraint intel_glm_pebs_event_constraints[] = {
 
 struct event_constraint intel_grt_pebs_event_constraints[] = {
 	/* Allow all events as PEBS with no flags */
-	INTEL_HYBRID_LAT_CONSTRAINT(0x5d0, 0x3),
-	INTEL_HYBRID_LAT_CONSTRAINT(0x6d0, 0x3f),
+	INTEL_HYBRID_LDLAT_CONSTRAINT(0x5d0, 0x3),
+	INTEL_HYBRID_STLAT_CONSTRAINT(0x6d0, 0x3f),
 	EVENT_CONSTRAINT_END
 };