[PATCH] kprobes: bugfix: try_module_get even if calling_mod is NULL
From: Masami Hiramatsu
Date: Wed Nov 05 2008 - 19:08:29 EST
Get probed module even if the caller is in the kernel core code.
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
>> One question, off topic.
>> If calling_mod is NULL, no try_module_get(), is that OK?
>
> Good question. Currently, kprobes is called only from kernel modules,
> so calling_mod should be always !NULL.
> However, it should be fixed, because the logic is not correct.
Thank you so much. So here is the additional bugfix patch.
kernel/kprobes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: 2.6.28-rc3/kernel/kprobes.c
===================================================================
--- 2.6.28-rc3.orig/kernel/kprobes.c
+++ 2.6.28-rc3/kernel/kprobes.c
@@ -634,7 +634,7 @@ static int __kprobes __register_kprobe(s
* avoid incrementing the module refcount, so as to allow
* unloading of self probing modules.
*/
- if (calling_mod && calling_mod != probed_mod) {
+ if (calling_mod != probed_mod) {
if (unlikely(!try_module_get(probed_mod))) {
preempt_enable();
return -EINVAL;
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@xxxxxxxxxx
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