From: Peter Zijlstra peterz@infradead.org
[ 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@linux.intel.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Tested-by: Kan Liang kan.liang@linux.intel.com Link: https://lkml.kernel.org/r/YMsy7BuGT8nBTspT@hirez.programming.kicks-ass.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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);