On Wed, Feb 14, 2018 at 7:39 AM, Ingo Molnar <mi...@kernel.org> wrote: > > * Dave Hansen <dave.han...@intel.com> wrote: > >> On 02/13/2018 06:27 PM, Josh Poimboeuf wrote: >> > --- a/arch/x86/entry/entry_64.S >> > +++ b/arch/x86/entry/entry_64.S >> > @@ -1167,10 +1167,10 @@ ENTRY(paranoid_exit) >> > UNWIND_HINT_REGS >> > DISABLE_INTERRUPTS(CLBR_ANY) >> > TRACE_IRQS_OFF_DEBUG >> > + RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 >> > testl %ebx, %ebx /* swapgs needed? */ >> > jnz .Lparanoid_exit_no_swapgs >> > TRACE_IRQS_IRETQ >> > - RESTORE_CR3 scratch_reg=%rbx save_reg=%r14 >> > SWAPGS_UNSAFE_STACK >> > jmp .Lparanoid_exit_restore >> > .Lparanoid_exit_no_swapgs: >> >> TRACE_IRQS_* call non-entry functions that are not mapped by the user >> CR3. How can this possibly work? What am I missing? > > How about something like the patch below? (Totally untested) > > Thanks, > > Ingo > --- > arch/x86/entry/entry_64.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S > index cd216c9431e1..8971bd64d515 100644 > --- a/arch/x86/entry/entry_64.S > +++ b/arch/x86/entry/entry_64.S > @@ -1175,6 +1175,7 @@ ENTRY(paranoid_exit) > jmp .Lparanoid_exit_restore > .Lparanoid_exit_no_swapgs: > TRACE_IRQS_IRETQ_DEBUG > + RESTORE_CR3 scratch_reg=%rbx save_reg=%r14 > .Lparanoid_exit_restore: > jmp restore_regs_and_return_to_kernel > END(paranoid_exit)
Reviewed-by: Andy Lutomirski <l...@kernel.org>
