On Thu, Aug 13, 2020 at 12:50:26PM +0200, Sebastian Andrzej Siewior wrote: > The pte lock is never acquired in-IRQ context so it does not require the > interrupts to be disabled. > > RT complains here because the spinlock_t must not be acquired with > disabled interrupts. > > use_temporary_mm() expects interrupts to be off because it invokes > switch_mm_irqs_off() and uses per-CPU (current active mm) data. > > Move the PTE lock handling outside the interrupt disabled region. > > Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Agreed, this should be fine. Acked-by; Peter Zijlstra (Intel) <[email protected]> > --- > v1…v2: Reword the patch description. > > arch/x86/kernel/alternative.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > --- a/arch/x86/kernel/alternative.c > +++ b/arch/x86/kernel/alternative.c > @@ -875,8 +875,6 @@ static void *__text_poke(void *addr, con > */ > BUG_ON(!pages[0] || (cross_page_boundary && !pages[1])); > > - local_irq_save(flags); > - > /* > * Map the page without the global bit, as TLB flushing is done with > * flush_tlb_mm_range(), which is intended for non-global PTEs. > @@ -893,6 +891,8 @@ static void *__text_poke(void *addr, con > */ > VM_BUG_ON(!ptep); > > + local_irq_save(flags); > + > pte = mk_pte(pages[0], pgprot); > set_pte_at(poking_mm, poking_addr, ptep, pte); > > @@ -942,8 +942,8 @@ static void *__text_poke(void *addr, con > */ > BUG_ON(memcmp(addr, opcode, len)); > > - pte_unmap_unlock(ptep, ptl); > local_irq_restore(flags); > + pte_unmap_unlock(ptep, ptl); > return addr; > } >
