Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Thu, 13 Aug 2020 12:50:26 +0200 | From | Sebastian Andrzej Siewior <> | Subject | [PATCH v2] x86/alternatives: Let __text_poke() acquire the pte lock with enabled interrupts |
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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 <bigeasy@linutronix.de> --- 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; }
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