Messages in this thread | | | Date | Wed, 20 Feb 2019 09:47:05 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access kernel memory that can fault |
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On Wed, 20 Feb 2019 14:57:31 +0100 Jann Horn <jannh@google.com> wrote:
> > (*) BTW, there is another concern to use _from_user APIs in kprobe. Are those > > APIs might sleep?? > > If you want to access userspace without sleeping, and ignore data in > non-present pages, you can do `pagefault_disable(); err = > __copy_from_user_inatomic(...); pagefault_enable();`. (Actually, maybe > the kernel should have a helper for that...)
I was about to say pretty much the same thing (about using _inatomic()), but yeah, we should also have a helper function if we don't already to include the page_fault_disable/enable() too.
-- Steve
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