On Tue, Oct 19, 2021 at 1:45 PM Steven Rostedt [off-list ref] wrote:

On Wed, 15 Sep 2021 19:52:46 +0000
Kalesh Singh [off-list ref] wrote:

quoted

+static u64 hist_field_div(struct hist_field *hist_field,
+                        struct tracing_map_elt *elt,
+                        struct trace_buffer *buffer,
+                        struct ring_buffer_event *rbe,
+                        void *event)
+{
+     struct hist_field *operand1 = hist_field->operands[0];
+     struct hist_field *operand2 = hist_field->operands[1];
+
+     u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event);
+     u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event);
+
+     /* Return -1 for the undefined case */
+     if (!val2)
+             return -1;
+
+     return val1 / val2;

This wont work on x86 32 bit machines, as u64 division will trigger
floating point arithmetic by the compiler, and cause a fault.

Thanks for catching this. I'll address it in the next version.

- Kalesh

You'll need to use one of the div64() helpers.

-- Steve

quoted

+}
+