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Commit 7f6878a3 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt
Browse files

tracing/kprobe: Update symbol reference when loading module 



Since the address of a module-local variable can only be
solved after the target module is loaded, the symbol
fetch-argument should be updated when loading target
module.

Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/r/20110627072703.6528.75042.stgit@fedora15


Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 61424318

kernel/trace/trace_kprobe.c

+36 −1
Original line number Diff line number Diff line
@@ -343,6 +343,14 @@ DEFINE_BASIC_FETCH_FUNCS(deref) 
DEFINE_FETCH_deref(string)

DEFINE_FETCH_deref(string_size)



static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)

{

	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))

		update_deref_fetch_param(data->orig.data);

	else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))

		update_symbol_cache(data->orig.data);

}



static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)

{

	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
@@ -376,6 +384,19 @@ DEFINE_BASIC_FETCH_FUNCS(bitfield) 
#define fetch_bitfield_string NULL

#define fetch_bitfield_string_size NULL



static __kprobes void

update_bitfield_fetch_param(struct bitfield_fetch_param *data)

{

	/*

	 * Don't check the bitfield itself, because this must be the

	 * last fetch function.

	 */

	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))

		update_deref_fetch_param(data->orig.data);

	else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))

		update_symbol_cache(data->orig.data);

}



static __kprobes void

free_bitfield_fetch_param(struct bitfield_fetch_param *data)

{
@@ -389,6 +410,7 @@ free_bitfield_fetch_param(struct bitfield_fetch_param *data) 
		free_symbol_cache(data->orig.data);

	kfree(data);

}



/* Default (unsigned long) fetch type */

#define __DEFAULT_FETCH_TYPE(t) u##t

#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
@@ -680,6 +702,16 @@ static struct trace_probe *alloc_trace_probe(const char *group, 
	return ERR_PTR(ret);

}



static void update_probe_arg(struct probe_arg *arg)

{

	if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))

		update_bitfield_fetch_param(arg->fetch.data);

	else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))

		update_deref_fetch_param(arg->fetch.data);

	else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))

		update_symbol_cache(arg->fetch.data);

}



static void free_probe_arg(struct probe_arg *arg)

{

	if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
@@ -749,11 +781,14 @@ static void disable_trace_probe(struct trace_probe *tp, int flag) 
/* Internal register function - just handle k*probes and flags */

static int __register_trace_probe(struct trace_probe *tp)

{

	int ret;

	int i, ret;



	if (trace_probe_is_registered(tp))

		return -EINVAL;



	for (i = 0; i < tp->nr_args; i++)

		update_probe_arg(&tp->args[i]);



	/* Set/clear disabled flag according to tp->flag */

	if (trace_probe_is_enabled(tp))

		tp->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;