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    SubjectRe: [PATCH v33 15/21] x86/vdso: Add support for exception fixup in vDSO functions
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    Andy Lutomirski <luto@amacapital.net> writes:
    > On Tue, Jun 30, 2020 at 1:41 AM Borislav Petkov <bp@alien8.de> wrote:
    >>
    >> On Mon, Jun 29, 2020 at 11:00:55PM -0700, Sean Christopherson wrote:
    >> > E.g. the vDSO function should get the fixup even if userspace screws
    >> > up mmap() and invokes __vdso_sgx_enter_enclave() without being tagged
    >> > an SGX task.
    >>
    >> I sincerely hope you don't mean this seriously.
    >>
    >> Please add a member to task_struct which denotes that a task is an
    >> sgx task, test that member where needed and forget real quickly about
    >> running *any* *fixup* for unrelated tasks.
    >
    > I don't see the problem. If you call this magic vDSO function and get
    > a fault, it gets handled. What's the failure mode?

    Handled by some definition of handled. If a random user space tasks ends
    up in that function then it will not die as it would otherwise, but I
    don't see a real issue with that either.

    Thanks,

    tglx

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