tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined

commit b8299d362d0837ae39e87e9019ebe6b736e0f035 upstream.

On some archs with some configurations, MCOUNT_INSN_SIZE is not defined, and
this makes the stack tracer fail to compile. Just define it to zero in this
case.

Link: https://lore.kernel.org/r/202001020219.zvE3vsty%lkp@intel.com
Fixes: 4df297129f622 ("tracing: Remove most or all of stack tracer stack size from stack_max_size")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 8a4e5cb66a4c4c1b9726f942e3e54b8e52a45ff5..27eb7e96dabe5b6b1fafd0e6e1548e72fdf9d7ef 100644 (file)
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -182,6 +182,11 @@ check_stack(unsigned long ip, unsigned long *stack)
        local_irq_restore(flags);
 }
 
+/* Some archs may not define MCOUNT_INSN_SIZE */
+#ifndef MCOUNT_INSN_SIZE
+# define MCOUNT_INSN_SIZE 0
+#endif
+
 static void
 stack_trace_call(unsigned long ip, unsigned long parent_ip,
                 struct ftrace_ops *op, struct pt_regs *pt_regs)