lkml.org 
[lkml]   [2018]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2] tracing: kprobes: Prohibit probing on notrace functions
Date
From: Masami Hiramatsu <mhiramat@kernel.org>

Prohibit kprobe-events probing on notrace function.
Since probing on the notrace function can cause recursive
event call. In most case those are just skipped, but
in some case it falls into infinite recursive call.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com>
---
kernel/trace/trace_kprobe.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index daa8157..952dc2a 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -487,6 +487,23 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
return ret;
}

+#ifdef CONFIG_KPROBES_ON_FTRACE
+static bool within_notrace_func(struct trace_kprobe *tk)
+{
+ unsigned long offset, size, addr;
+
+ addr = kallsyms_lookup_name(trace_kprobe_symbol(tk));
+ addr += trace_kprobe_offset(tk);
+
+ if (!kallsyms_lookup_size_offset(addr, &size, &offset))
+ return true; /* Out of range. */
+
+ return !ftrace_location_range(addr - offset, addr - offset + size);
+}
+#else
+#define within_notrace_func(tk) (false)
+#endif
+
/* Internal register function - just handle k*probes and flags */
static int __register_trace_kprobe(struct trace_kprobe *tk)
{
@@ -495,6 +512,12 @@ static int __register_trace_kprobe(struct trace_kprobe *tk)
if (trace_probe_is_registered(&tk->tp))
return -EINVAL;

+ if (within_notrace_func(tk)) {
+ pr_warn("Could not probe notrace function %s\n",
+ trace_kprobe_symbol(tk));
+ return -EINVAL;
+ }
+
for (i = 0; i < tk->tp.nr_args; i++)
traceprobe_update_arg(&tk->tp.args[i]);

--
2.7.4
\
 
 \ /
  Last update: 2018-07-15 22:06    [W:0.167 / U:0.836 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site