FAILED: patch "[PATCH] coresight: etb10: Do not call smp_processor_id from" failed to apply to 5.1-stable tree

The patch below does not apply to the 5.1-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 <[email protected]>.

thanks,

greg k-h

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

From 730766bae3280a25d40ea76a53dc6342e84e6513 Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <[email protected]>
Date: Thu, 20 Jun 2019 16:12:36 -0600
Subject: [PATCH] coresight: etb10: Do not call smp_processor_id from
preemptible

During a perf session we try to allocate buffers on the "node" associated with the CPU the event is bound to. If it is not bound to a CPU, we use the current CPU node, using smp_processor_id(). However this is unsafe in a pre-emptible context and could generate the splats as below :

 BUG: using smp_processor_id() in preemptible [00000000] code: perf/2544

Use NUMA_NO_NODE hint instead of using the current node for events not bound to CPUs.

index d5b9edecf76e..3810290e6d07 100644
@@ -374,12 +374,10 @@ static void *etb_alloc_buffer(struct coresight_device *csdev,
 			      struct perf_event *event, void **pages,
 			      int nr_pages, bool overwrite)
 {
-	int node, cpu = event->cpu;
+	int node;
 	struct cs_buffers *buf;
 
-	if (cpu == -1)
-		cpu = smp_processor_id();
-	node = cpu_to_node(cpu);
+	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
 
 	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
 	if (!buf)