[PATCH] i386: Fix race in iounmap
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>
diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
index db06f73..ab54279 100644
--- a/arch/i386/mm/ioremap.c
+++ b/arch/i386/mm/ioremap.c
@@ -238,19 +238,21 @@
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);
}