[PATCH 5.4 05/76] tracing/kprobes: Do the notrace functions check without kprobes on ftrace

Greg Kroah-Hartman
2021-01-18T19:19:31Z

From: Masami Hiramatsu <mhiramat@kernel.org>

commit 7bb83f6fc4ee84e95d0ac0d14452c2619fb3fe70 upstream.

Enable the notrace function check on the architecture which doesn't
support kprobes on ftrace but support dynamic ftrace. This notrace
function check is not only for the kprobes on ftrace but also
sw-breakpoint based kprobes.
Thus there is no reason to limit this check for the arch which
supports kprobes on ftrace.

This also changes the dependency of Kconfig. Because kprobe event
uses the function tracer's address list for identifying notrace
function, if the CONFIG_DYNAMIC_FTRACE=n, it can not check whether
the target function is notrace or not.

Link: https://lkml.kernel.org/r/20210105065730.2634785-1-naveen.n.rao@linux.vnet.ibm.com
Link: https://lkml.kernel.org/r/161007957862.114704.4512260007555399463.stgit@devnote2

Cc: stable@vger.kernel.org
Fixes: 45408c4f92506 ("tracing: kprobes: Prohibit probing on notrace function")
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/trace/Kconfig | 2 +-
kernel/trace/trace_kprobe.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -478,7 +478,7 @@ config KPROBE_EVENTS
config KPROBE_EVENTS_ON_NOTRACE
bool "Do NOT protect notrace function from kprobe events"
depends on KPROBE_EVENTS
- depends on KPROBES_ON_FTRACE
+ depends on DYNAMIC_FTRACE
default n
help
This is only for the developers who want to debug ftrace itself
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -433,7 +433,7 @@ static int disable_trace_kprobe(struct t
return 0;
}

-#if defined(CONFIG_KPROBES_ON_FTRACE) && \
+#if defined(CONFIG_DYNAMIC_FTRACE) && \
!defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
static bool __within_notrace_func(unsigned long addr)
{