Messages in this thread Patch in this message | | | From | Sebastian Andrzej Siewior <> | Subject | [PATCH] x86/alternatives: Let __text_poke() acquire the pte lock with enabled interrupts | Date | Mon, 6 Jul 2020 18:42:15 +0200 |
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The pte lock is never acquired from an IRQ-off region 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 local_irq_save() after the the pte lock has been acquired. Move local_irq_restore() after the pte lock has been released.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- arch/x86/kernel/alternative.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 8fd39ff74a499..7c59a87ebbde8 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -872,8 +872,6 @@ static void *__text_poke(void *addr, const void *opcode, size_t len) */ 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. @@ -890,6 +888,8 @@ static void *__text_poke(void *addr, const void *opcode, size_t len) */ VM_BUG_ON(!ptep); + local_irq_save(flags); + pte = mk_pte(pages[0], pgprot); set_pte_at(poking_mm, poking_addr, ptep, pte); @@ -939,8 +939,8 @@ static void *__text_poke(void *addr, const void *opcode, size_t len) */ BUG_ON(memcmp(addr, opcode, len)); - pte_unmap_unlock(ptep, ptl); local_irq_restore(flags); + pte_unmap_unlock(ptep, ptl); return addr; } -- 2.27.0
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