Re: [PATCH] kprobes: disable preempt for module_text_address()

From: Masami Hiramatsu
Date: Wed Nov 05 2008 - 18:09:01 EST


Hiroshi Shimamoto wrote:
>> if (probed_mod) {
>> - struct module *calling_mod = module_text_address(called_from);
>> + struct module *calling_mod;
>> + calling_mod = __module_text_address(called_from);
>> /*
>> * We must allow modules to probe themself and in this case
>> * avoid incrementing the module refcount, so as to allow
>> * unloading of self probing modules.
>> */
>> if (calling_mod && calling_mod != probed_mod) {
>
> 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,

--
Masami Hiramatsu

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

e-mail: mhiramat@xxxxxxxxxx

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