Remove called_from argument from kprobes which had been used for preventing
self-refering of kernel module. However, since we don't keep module's refcount
after registering kprobe any more, there is no reason to check that.

This patch also simplifies registering/unregistering functions because we don't
need to use __builtin_return_address(0) which was passed to called_from.

Signed-off-by: Masami Hiramatsu
---
kernel/kprobes.c | 70 +++++++++++--------------------------------------------
1 file changed, 14 insertions(+), 56 deletions(-)

Index: 2.6.28-rc4/kernel/kprobes.c
================================================== =================
--- 2.6.28-rc4.orig/kernel/kprobes.c
+++ 2.6.28-rc4/kernel/kprobes.c
@@ -641,8 +641,7 @@ static kprobe_opcode_t __kprobes *kprobe
return (kprobe_opcode_t *)(((char *)addr) + p->offset);
}

-static int __kprobes __register_kprobe(struct kprobe *p,
- unsigned long called_from)
+int __kprobes register_kprobe(struct kprobe *p)
{
int ret = 0;
struct kprobe *old_p;
@@ -673,13 +672,10 @@ static int __kprobes __register_kprobe(s
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
- if (calling_mod != probed_mod) {
- if (unlikely(!try_module_get(probed_mod))) {
- preempt_enable();
- return -EINVAL;
- }
- } else
- probed_mod = NULL;
+ if (unlikely(!try_module_get(probed_mod))) {
+ preempt_enable();
+ return -EINVAL;
+ }
}
preempt_enable();

@@ -773,15 +769,14 @@ static void __kprobes __unregister_kprob
}
}

-static int __kprobes __register_kprobes(struct kprobe **kps, int num,
- unsigned long called_from)
+int __kprobes register_kprobes(struct kprobe **kps, int num)
{
int i, ret = 0;

if (num <= 0)
return -EINVAL;
for (i = 0; i < num; i++) {
- ret = __register_kprobe(kps[i], called_from);
+ ret = register_kprobe(kps[i]);
if (ret < 0) {
if (i > 0)
unregister_kprobes(kps, i);
@@ -791,26 +786,11 @@ static int __kprobes __register_kprobes(
return ret;
}

-/*
- * Registration and unregistration functions for kprobe.
- */
-int __kprobes register_kprobe(struct kprobe *p)
-{
- return __register_kprobes(&p, 1,
- (unsigned long)__builtin_return_address(0));
-}
-
void __kprobes unregister_kprobe(struct kprobe *p)
{
unregister_kprobes(&p, 1);
}

-int __kprobes register_kprobes(struct kprobe **kps, int num)
-{
- return __register_kprobes(kps, num,
- (unsigned long)__builtin_return_address(0));
-}
-
void __kprobes unregister_kprobes(struct kprobe **kps, int num)
{
int i;
@@ -839,8 +819,7 @@ unsigned long __weak arch_deref_entry_po
return (unsigned long)entry;
}

-static int __kprobes __register_jprobes(struct jprobe **jps, int num,
- unsigned long called_from)
+int __kprobes register_jprobes(struct jprobe **jps, int num)
{
struct jprobe *jp;
int ret = 0, i;
@@ -858,7 +837,7 @@ static int __kprobes __register_jprobes(
/* Todo: Verify probepoint is a function entry point */
jp->kp.pre_handler = setjmp_pre_handler;
jp->kp.break_handler = longjmp_break_handler;
- ret = __register_kprobe(&jp->kp, called_from);
+ ret = register_kprobe(&jp->kp);
}
if (ret < 0) {
if (i > 0)
@@ -871,8 +850,7 @@ static int __kprobes __register_jprobes(

int __kprobes register_jprobe(struct jprobe *jp)
{
- return __register_jprobes(&jp, 1,
- (unsigned long)__builtin_return_address(0));
+ return register_jprobes(&jp, 1);
}

void __kprobes unregister_jprobe(struct jprobe *jp)
@@ -880,12 +858,6 @@ void __kprobes unregister_jprobe(struct
unregister_jprobes(&jp, 1);
}

-int __kprobes register_jprobes(struct jprobe **jps, int num)
-{
- return __register_jprobes(jps, num,
- (unsigned long)__builtin_return_address(0));
-}
-
void __kprobes unregister_jprobes(struct jprobe **jps, int num)
{
int i;
@@ -948,8 +920,7 @@ static int __kprobes pre_handler_kretpro
return 0;
}

-static int __kprobes __register_kretprobe(struct kretprobe *rp,
- unsigned long called_from)
+int __kprobes register_kretprobe(struct kretprobe *rp)
{
int ret = 0;
struct kretprobe_instance *inst;
@@ -995,21 +966,20 @@ static int __kprobes __register_kretprob

rp->nmissed = 0;
/* Establish function entry probe point */
- ret = __register_kprobe(&rp->kp, called_from);
+ ret = register_kprobe(&rp->kp);
if (ret != 0)
free_rp_inst(rp);
return ret;
}

-static int __kprobes __register_kretprobes(struct kretprobe **rps, int num,
- unsigned long called_from)
+int __kprobes register_kretprobes(struct kretprobe **rps, int num)
{
int ret = 0, i;

if (num <= 0)
return -EINVAL;
for (i = 0; i < num; i++) {
- ret = __register_kretprobe(rps[i], called_from);
+ ret = register_kretprobe(rps[i]);
if (ret < 0) {
if (i > 0)
unregister_kretprobes(rps, i);
@@ -1019,23 +989,11 @@ static int __kprobes __register_kretprob
return ret;
}

-int __kprobes register_kretprobe(struct kretprobe *rp)
-{
- return __register_kretprobes(&rp, 1,
- (unsigned long)__builtin_return_address(0));
-}
-
void __kprobes unregister_kretprobe(struct kretprobe *rp)
{
unregister_kretprobes(&rp, 1);
}

-int __kprobes register_kretprobes(struct kretprobe **rps, int num)
-{
- return __register_kretprobes(rps, num,
- (unsigned long)__builtin_return_address(0));
-}
-
void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
{
int i;

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/