Messages in this thread | | | Date | Mon, 2 Mar 2020 18:38:52 +0100 | From | Greg KH <> | Subject | Re: [PATCH v2 2/3] binder: do not initialize locals passed to copy_from_user() |
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On Mon, Mar 02, 2020 at 02:04:29PM +0100, glider@google.com wrote: > Certain copy_from_user() invocations in binder.c are known to > unconditionally initialize locals before their first use, like e.g. in > the following case: > > struct binder_transaction_data tr; > if (copy_from_user(&tr, ptr, sizeof(tr))) > return -EFAULT; > > In such cases enabling CONFIG_INIT_STACK_ALL leads to insertion of > redundant locals initialization that the compiler fails to remove. > To work around this problem till Clang can deal with it, we apply > __no_initialize to local Binder structures.
I would like to see actual benchmark numbers showing this is needed/useful otherwise it's going to just be random people adding this marking to random places with no real reason.
thanks,
greg k-h
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