[PATCH 4.9 33/44] kprobes: Mark ftrace mcount handler functions nokprobe

Greg Kroah-Hartman
2019-04-24T17:58:27Z

From: Masami Hiramatsu <mhiramat@kernel.org>

commit fabe38ab6b2bd9418350284c63825f13b8a6abba upstream.

Mark ftrace mcount handler functions nokprobe since
probing on these functions with kretprobe pushes
return address incorrectly on kretprobe shadow stack.

Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Tested-by: Andrea Righi <righi.andrea@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/155094062044.6137.6419622920568680640.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/ftrace.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -32,6 +32,7 @@
#include <linux/list.h>
#include <linux/hash.h>
#include <linux/rcupdate.h>
+#include <linux/kprobes.h>

#include <trace/events/sched.h>

@@ -5246,7 +5247,7 @@ void ftrace_reset_array_ops(struct trace
tr->ops->func = ftrace_stub;
}

-static inline void
+static nokprobe_inline void
__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ignored, struct pt_regs *regs)
{
@@ -5309,11 +5310,13 @@ static void ftrace_ops_list_func(unsigne
{
__ftrace_ops_list_func(ip, parent_ip, NULL, regs);
}
+NOKPROBE_SYMBOL(ftrace_ops_list_func);
#else
static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
{
__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
}
+NOKPROBE_SYMBOL(ftrace_ops_no_ops);
#endif

/*
@@ -5343,6 +5346,7 @@ static void ftrace_ops_assist_func(unsig
preempt_enable_notrace();
trace_clear_recursion(bit);
}
+NOKPROBE_SYMBOL(ftrace_ops_assist_func);

/**
* ftrace_ops_get_func - get the function a trampoline should call