From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
[ Upstream commit 012669c740e6e2afa8bdb95394d06676f933dd2d ]
On HETEROGENEOUS hardware (ARM big.Little, Intel Alderlake etc.) each
CPU might have a different hardware PMU. Since each such PMU is
represented by a different struct pmu, but we only have a single HW
task context.
That means that the task context needs to switch PMU type when it
switches CPUs.
Not doing this means that ctx->pmu calls (pmu_{dis,en}able(),
{start,commit,cancel}_txn() etc.) are called against the wrong PMU and
things will go wobbly.
Fixes: f83d2f91d259 ("perf/x86/intel: Add Alder Lake Hybrid support")
Reported-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Tested-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/YMsy7BuGT8nBTspT@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/events/core.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index fe88d6eea3c2..9ebac2a79467 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3821,9 +3821,16 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx,
struct task_struct *task)
{
struct perf_cpu_context *cpuctx;
- struct pmu *pmu = ctx->pmu;
+ struct pmu *pmu;
cpuctx = __get_cpu_context(ctx);
+
+ /*
+ * HACK: for HETEROGENEOUS the task context might have switched to a
+ * different PMU, force (re)set the context,
+ */
+ pmu = ctx->pmu = cpuctx->ctx.pmu;
+
if (cpuctx->task_ctx == ctx) {
if (cpuctx->sched_cb_usage)
__perf_pmu_sched_task(cpuctx, true);
--
2.30.2
