Commit ebad825c authored Aug 01, 2018 by Linus Torvalds

ia64: mark special ia64 memory areas anonymous



Commit bfd40eaf ("mm: fix vma_is_anonymous() false-positives") made
newly allocated vma's have a dummy vm_ops field so that they wouldn't be
mistaken for anonymous mappings, and if you wanted an anonymous vma you
had to explicitly say so by calling "vma_set_anonymous()" on it.

However, it missed the two special vmas that ia64 processes have: the
register backing store and the NaT page.  So they wouldn't actually act
like anonymous ranges, and page faults on them caused a SIGBUS rather
than the creation of a new anon page in them.

That obviously will make any ia64 binary very unhappy indeed, and the
boot fails early.

Fixes: bfd40eaf ("mm: fix vma_is_anonymous() false-positives")
Reported-by: Tony Luck <tony.luck@intel.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 37b71411

arch/ia64/mm/init.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -116,6 +116,7 @@ ia64_init_addr_space (void)
		*/
		vma = vm_area_alloc(current->mm);
		if (vma) {
		vma_set_anonymous(vma);
		vma->vm_start = current->thread.rbs_bot & PAGE_MASK;
		vma->vm_end = vma->vm_start + PAGE_SIZE;
		vma->vm_flags = VM_DATA_DEFAULT_FLAGS\|VM_GROWSUP\|VM_ACCOUNT;
		@@ -133,6 +134,7 @@ ia64_init_addr_space (void)
		if (!(current->personality & MMAP_PAGE_ZERO)) {
		vma = vm_area_alloc(current->mm);
		if (vma) {
		vma_set_anonymous(vma);
		vma->vm_end = PAGE_SIZE;
		vma->vm_page_prot = __pgprot(pgprot_val(PAGE_READONLY) \| _PAGE_MA_NAT);
		vma->vm_flags = VM_READ \| VM_MAYREAD \| VM_IO \|

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