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[PATCH] i386: Fix race in iounmap

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We need to hold the vmlist_lock while doing change_page_attr, otherwise we
could reset someone else's mapping.

Requires previous patch to add __remove_vm_area

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andi Kleen 2005-05-20 14:27:57 -07:00 committed by Linus Torvalds
parent 7856dfeb23
commit 4057923614
1 changed files with 6 additions and 4 deletions
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10
arch/i386/mm/ioremap.c
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@ -238,19 +238,21 @@ void iounmap(volatile void __iomem *addr)
addr < phys_to_virt(ISA_END_ADDRESS))
return;
p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
write_lock(&vmlist_lock);
p = __remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
if (!p) {
printk("__iounmap: bad address %p\n", addr);
return;
printk("iounmap: bad address %p\n", addr);
goto out_unlock;
}
if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
/* p->size includes the guard page, but cpa doesn't like that */
change_page_attr(virt_to_page(__va(p->phys_addr)),
p->size >> PAGE_SHIFT,
PAGE_KERNEL);
global_flush_tlb();
}
out_unlock:
write_unlock(&vmlist_lock);
kfree(p);
}