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[PATCH] x86_64: Fixed guard page handling again in iounmap
Caused oopses again. Also fix potential mismatch in checking if change_page_attr was needed. To do it without races I needed to change mm/vmalloc.c to export a __remove_vm_area that does not take vmlist lock. Noticed by Terence Ripperda and based on a patch of his. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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c4d1fcf3a2
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7856dfeb23
@ -133,7 +133,7 @@ ioremap_change_attr(unsigned long phys_addr, unsigned long size,
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unsigned long flags)
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{
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int err = 0;
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if (flags && phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) {
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if (phys_addr + size - 1 < (end_pfn_map << PAGE_SHIFT)) {
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unsigned long npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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unsigned long vaddr = (unsigned long) __va(phys_addr);
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@ -214,7 +214,7 @@ void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned l
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remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
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return NULL;
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}
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if (ioremap_change_attr(phys_addr, size, flags) < 0) {
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if (flags && ioremap_change_attr(phys_addr, size, flags) < 0) {
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area->flags &= 0xffffff;
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vunmap(addr);
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return NULL;
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@ -251,7 +251,7 @@ void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
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void iounmap(volatile void __iomem *addr)
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{
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struct vm_struct *p, **pprev;
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struct vm_struct *p;
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if (addr <= high_memory)
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return;
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@ -260,24 +260,11 @@ void iounmap(volatile void __iomem *addr)
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return;
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write_lock(&vmlist_lock);
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for (p = vmlist, pprev = &vmlist; p != NULL; pprev = &p->next, p = *pprev)
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if (p->addr == (void *)(PAGE_MASK & (unsigned long)addr))
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break;
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if (!p) {
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printk("__iounmap: bad address %p\n", addr);
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goto out_unlock;
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}
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*pprev = p->next;
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unmap_vm_area(p);
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if ((p->flags >> 20) &&
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p->phys_addr + p->size - 1 < virt_to_phys(high_memory)) {
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/* p->size includes the guard page, but cpa doesn't like that */
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change_page_attr_addr((unsigned long)__va(p->phys_addr),
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p->size >> PAGE_SHIFT,
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PAGE_KERNEL);
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global_flush_tlb();
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}
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out_unlock:
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p = __remove_vm_area((void *)((unsigned long)addr & PAGE_MASK));
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if (!p)
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printk("iounmap: bad address %p\n", addr);
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else if (p->flags >> 20)
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ioremap_change_attr(p->phys_addr, p->size, 0);
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write_unlock(&vmlist_lock);
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kfree(p);
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}
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@ -41,6 +41,7 @@ extern struct vm_struct *get_vm_area(unsigned long size, unsigned long flags);
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extern struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
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unsigned long start, unsigned long end);
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extern struct vm_struct *remove_vm_area(void *addr);
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extern struct vm_struct *__remove_vm_area(void *addr);
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extern int map_vm_area(struct vm_struct *area, pgprot_t prot,
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struct page ***pages);
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extern void unmap_vm_area(struct vm_struct *area);
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45
mm/vmalloc.c
45
mm/vmalloc.c
@ -248,6 +248,28 @@ struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
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return __get_vm_area(size, flags, VMALLOC_START, VMALLOC_END);
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}
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/* Caller must hold vmlist_lock */
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struct vm_struct *__remove_vm_area(void *addr)
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{
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struct vm_struct **p, *tmp;
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for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) {
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if (tmp->addr == addr)
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goto found;
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}
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return NULL;
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found:
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unmap_vm_area(tmp);
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*p = tmp->next;
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/*
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* Remove the guard page.
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*/
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tmp->size -= PAGE_SIZE;
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return tmp;
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}
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/**
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* remove_vm_area - find and remove a contingous kernel virtual area
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*
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@ -255,30 +277,15 @@ struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
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*
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* Search for the kernel VM area starting at @addr, and remove it.
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* This function returns the found VM area, but using it is NOT safe
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* on SMP machines.
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* on SMP machines, except for its size or flags.
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*/
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struct vm_struct *remove_vm_area(void *addr)
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{
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struct vm_struct **p, *tmp;
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struct vm_struct *v;
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write_lock(&vmlist_lock);
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for (p = &vmlist ; (tmp = *p) != NULL ;p = &tmp->next) {
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if (tmp->addr == addr)
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goto found;
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}
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v = __remove_vm_area(addr);
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write_unlock(&vmlist_lock);
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return NULL;
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found:
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unmap_vm_area(tmp);
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*p = tmp->next;
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write_unlock(&vmlist_lock);
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/*
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* Remove the guard page.
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*/
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tmp->size -= PAGE_SIZE;
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return tmp;
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return v;
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}
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void __vunmap(void *addr, int deallocate_pages)
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