The following commit has been merged into the x86/urgent branch of tip: Commit-ID: a6d996cbd38b42341ad3fce74506b9fdc280e395 Gitweb: https://git.kernel.org/tip/a6d996cbd38b42341ad3fce74506b9fdc280e395 Author: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> AuthorDate: Thu, 13 Aug 2020 12:50:26 +02:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Thu, 13 Aug 2020 14:11:54 +02:00 x86/alternatives: Acquire pte lock with interrupts enabled pte lock is never acquired in-IRQ context so it does not require interrupts to be disabled. The lock is a regular spinlock which cannot be acquired with interrupts disabled on RT. RT complains about pte_lock() in __text_poke() because it's invoked after disabling interrupts. __text_poke() has to disable interrupts as 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@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by; Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200813105026.bvugytmsso6muljw@xxxxxxxxxxxxx --- 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 c826cdd..34a1b85 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -874,8 +874,6 @@ 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. @@ -892,6 +890,8 @@ 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); @@ -941,8 +941,8 @@ 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; }
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