Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 49e9a539 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Greg Kroah-Hartman
Browse files

tracing/kprobe: Check whether the non-suffixed symbol is notrace 

[ Upstream commit c7411a1a126f649be71526a36d4afac9e5aefa13 ]

Check whether the non-suffixed symbol is notrace, since suffixed
symbols are generated by the compilers for optimization. Based on
these suffixed symbols, notrace check might not work because
some of them are just a partial code of the original function.
(e.g. cold-cache (unlikely) code is separated from original
 function as FUNCTION.cold.XX)

For example, without this fix,
  # echo p device_add.cold.67 > /sys/kernel/debug/tracing/kprobe_events
  sh: write error: Invalid argument

  # cat /sys/kernel/debug/tracing/error_log
  [  135.491035] trace_kprobe: error: Failed to register probe event
    Command: p device_add.cold.67
               ^
  # dmesg | tail -n 1
  [  135.488599] trace_kprobe: Could not probe notrace function device_add.cold.67

With this,
  # echo p device_add.cold.66 > /sys/kernel/debug/tracing/kprobe_events
  # cat /sys/kernel/debug/kprobes/list
  ffffffff81599de9  k  device_add.cold.66+0x0    [DISABLED]

Actually, kprobe blacklist already did similar thing,
see within_kprobe_blacklist().

Link: http://lkml.kernel.org/r/157233790394.6706.18243942030937189679.stgit@devnote2



Fixes: 45408c4f ("tracing: kprobes: Prohibit probing on notrace function")
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 22508003

kernel/trace/trace_kprobe.c

+24 −3
Original line number Diff line number Diff line
@@ -519,11 +519,10 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) 


#if defined(CONFIG_KPROBES_ON_FTRACE) && \

	!defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)

static bool within_notrace_func(struct trace_kprobe *tk)

static bool __within_notrace_func(unsigned long addr)

{

	unsigned long offset, size, addr;

	unsigned long offset, size;



	addr = trace_kprobe_address(tk);

	if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))

		return false;
@@ -536,6 +535,28 @@ static bool within_notrace_func(struct trace_kprobe *tk) 
	 */

	return !ftrace_location_range(addr, addr + size - 1);

}



static bool within_notrace_func(struct trace_kprobe *tk)

{

	unsigned long addr = addr = trace_kprobe_address(tk);

	char symname[KSYM_NAME_LEN], *p;



	if (!__within_notrace_func(addr))

		return false;



	/* Check if the address is on a suffixed-symbol */

	if (!lookup_symbol_name(addr, symname)) {

		p = strchr(symname, '.');

		if (!p)

			return true;

		*p = '\0';

		addr = (unsigned long)kprobe_lookup_name(symname, 0);

		if (addr)

			return __within_notrace_func(addr);

	}



	return true;

}

#else

#define within_notrace_func(tk)	(false)

#endif