Commit 63503794 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt
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ftrace: Fix global function tracers that are not recursion safe 



If one of the function tracers set by the global ops is not recursion
safe, it can still be called directly without the added recursion
supplied by the ftrace infrastructure.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 05cbbf64

kernel/trace/ftrace.c

+16 −2
Original line number Diff line number Diff line
@@ -221,10 +221,24 @@ static void update_global_ops(void) 
	 * registered callers.

	 */

	if (ftrace_global_list == &ftrace_list_end ||

	    ftrace_global_list->next == &ftrace_list_end)

	    ftrace_global_list->next == &ftrace_list_end) {

		func = ftrace_global_list->func;

		/*

		 * As we are calling the function directly.

		 * If it does not have recursion protection,

		 * the function_trace_op needs to be updated

		 * accordingly.

		 */

		if (ftrace_global_list->flags & FTRACE_OPS_FL_RECURSION_SAFE)

			global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;

		else

			global_ops.flags &= ~FTRACE_OPS_FL_RECURSION_SAFE;

	} else {

		func = ftrace_global_list_func;

		/* The list has its own recursion protection. */

		global_ops.flags |= FTRACE_OPS_FL_RECURSION_SAFE;

	}





	/* If we filter on pids, update to use the pid function */

	if (!list_empty(&ftrace_pids)) {