Messages in this thread | | | Date | Tue, 2 Jun 2015 18:06:06 +0800 | From | Minfei Huang <> | Subject | Re: [PATCH] livepatch: add module locking around kallsyms calls |
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On 06/02/15 at 11:15am, Miroslav Benes wrote: > On Tue, 2 Jun 2015, Minfei Huang wrote: > > > - if (kallsyms_on_each_symbol(klp_verify_callback, &args)) > > > - return 0; > > > + mutex_lock(&module_mutex); > > > + ret = kallsyms_on_each_symbol(klp_verify_callback, &args); > > > + mutex_unlock(&module_mutex); > > > > > > > Hi. > > In livepatch code path, returning value 0 may represent the right, but > > sometime represent wrong, like the above function. > > > > Is it possible that we can wrap such function and return the unified > > value? Thus we can not confuse the returning value any more. > > Hi, > > I must admit I do not understand. Both klp_find_object_symbol and > klp_verify_vmlinux_symbol return 0 on success or -EINVAL. It is true that > kallsyms_on_each_symbol and module_kallsyms_on_each symbol are different. > That is why our kallsyms callbacks are different. See the implementation > of those. But that is the API. Is this what you are worried about? >
Sorry to confuse you about the unclear description.
Yes. kallsyms_on_each_symbol return 0 to imply the failure. I know we should comply the API which we call from the other module, but it may be better to wrap the API as a function, if the return value conflicts with current rule.
Otherwise it may confuse someone that the error message will be printed, although the return value is 0, like kallsyms_on_each_symbol.
But I do not insist my view.
Thanks Minfei
> > Otherwise annotation is appreciate.
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