linux/debian/patches/features/all/rt/0002-x86-highmem-add-a-alre...

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From 65513f34449eedb6b84c24a3583266534c1627e4 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon, 11 Mar 2013 17:09:55 +0100
Subject: [PATCH 2/6] x86/highmem: add a "already used pte" check
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.0/patches-4.0.4-rt1.tar.xz
This is a copy from kmap_atomic_prot().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/mm/iomap_32.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/mm/iomap_32.c
+++ b/arch/x86/mm/iomap_32.c
@@ -66,6 +66,8 @@ void *kmap_atomic_prot_pfn(unsigned long
type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+ WARN_ON(!pte_none(*(kmap_pte - idx)));
+
#ifdef CONFIG_PREEMPT_RT_FULL
current->kmap_pte[type] = pte;
#endif