[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH for-4.16] x86/shstk: Fix use of shadow stacks with XPTI active
Jan Beulich writes ("Re: [PATCH for-4.16] x86/shstk: Fix use of shadow stacks with XPTI active"): > On 02.11.2021 15:39, Andrew Cooper wrote: > > The call to setup_cpu_root_pgt(0) in smp_prepare_cpus() is too early. It > > clones the BSP's stack while the .data mapping is still in use, causing all > > mappings to be fully read read/write (and with no guard pages either). This > > ultimately causes #DF when trying to enter the dom0 kernel for the first > > time. > > > > Defer setting up BSPs XPTI pagetable until reinit_bsp_stack() after we've > > set > > up proper shadow stack permissions. > > > > Fixes: 60016604739b ("x86/shstk: Rework the stack layout to support shadow > > stacks") > > Fixes: b60ab42db2f0 ("x86/shstk: Activate Supervisor Shadow Stacks") > > Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> > > Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
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