Messages in this thread | | | From | "Edgecombe, Rick P" <> | Subject | Re: [PATCH v2 07/39] x86/cet: Add user control-protection fault handler | Date | Mon, 3 Oct 2022 18:12:13 +0000 |
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On Mon, 2022-10-03 at 17:01 +0300, Kirill A . Shutemov wrote: > On Thu, Sep 29, 2022 at 03:29:04PM -0700, Rick Edgecombe wrote: > > +#else > > +static void do_user_control_protection_fault(struct pt_regs *regs, > > + unsigned long > > error_code) > > +{ > > + WARN_ONCE(1, "User-mode control protection fault with shadow > > support disabled\n"); > > Why is this a warning, but runtime check for !X86_FEATURE_IBT and > !X86_FEATURE_SHSTK below is fatal?
It was a BUG() in the original KERNEL_IBT focused handler IIRC. There seems to be some renewed effort to stop doing those:
https://lore.kernel.org/all/20220923113426.52871-2-david@redhat.com/T/#u
...so I'll change it to a WARN for this. In the kernel specific portion of the handler, it also does a BUG on endbranch violation. I'll leave that one for this change.
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