From 9161a864ff88e800de50494da095af19832e9583 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 21 Aug 2018 22:04:57 +0900 Subject: [PATCH] tracing/kprobes: Fix to check notrace function with correct range Fix within_notrace_func() to check notrace function correctly. Since the ftrace_location_range(start, end) function checks the range inclusively (start <= ftrace-loc <= end), the end address must not include the entry address of next function. However, within_notrace_func() uses kallsyms_lookup_size_offset() to get the function size and calculate the end address from adding the size to the entry address. This means the end address is the entry address of the next function. In the result, within_notrace_func() fails to find notrace function if the next function of the target function is ftraced. Let's subtract 1 from the end address so that ftrace_location_range() can check it correctly. Link: http://lkml.kernel.org/r/153485669706.16611.17726752296213785504.stgit@devbox Fixes: commit 45408c4f9250 ("tracing: kprobes: Prohibit probing on notrace function") Reported-by: Michael Rodin Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_kprobe.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 65a4157a..ad384b3 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -513,7 +513,14 @@ static bool within_notrace_func(struct trace_kprobe *tk) if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) return false; - return !ftrace_location_range(addr - offset, addr - offset + size); + /* Get the entry address of the target function */ + addr -= offset; + + /* + * Since ftrace_location_range() does inclusive range check, we need + * to subtract 1 byte from the end address. + */ + return !ftrace_location_range(addr, addr + size - 1); } #else #define within_notrace_func(tk) (false) -- 2.7.4