Merge tag 'trace-v7.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fix from Steven Rostedt:

 - Fix CFI violation in probestub function

   The probestub is a function to allow tprobes to hook to a tracepoint
   to gain access to its parameters.

   The function itself is only referenced by the tracepoint structure
   which lives in the __tracepoint section. objtool explicitly ignores
   that section and when processing functions in the kernel, if it
   detects one that has no references it will seal it to have its ENDBR
   stripped on boot up.

   This means the probstub function will have its ENDBR stripped and if
   a tprobe is attached to it with IBT enabled, it will go *boom*.

* tag 'trace-v7.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix CFI violation in probestub being called by tprobes

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 763eea4d80d8..2d2b9f8cdda4 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -20,6 +20,7 @@
 #include <linux/rcupdate_trace.h>
 #include <linux/tracepoint-defs.h>
 #include <linux/static_call.h>
+#include <linux/cfi.h>
 
 struct module;
 struct tracepoint;
@@ -389,6 +390,13 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
 	void __probestub_##_name(void *__data, proto)			\
 	{								\
 	}								\
+	/*								\
+	 * Annotate the probestub 'CFI_NOSEAL' to stop objtool from	\
+	 * requesting the kernel remove the ENDBR, because the only	\
+	 * references to the function are in the __tracepoint section,	\
+	 * that objtool doesn't scan.					\
+	 */								\
+	CFI_NOSEAL(__probestub_##_name);				\
 	DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);	\
 	DEFINE_RUST_DO_TRACE(_name, TP_PROTO(proto), TP_ARGS(args))