Commit 02057967 authored Apr 14, 2015 by David Rientjes Committed by Linus Torvalds Apr 14, 2015

mm, hugetlb: abort __get_user_pages if current has been oom killed



If __get_user_pages() is faulting a significant number of hugetlb pages,
usually as the result of mmap(MAP_LOCKED), it can potentially allocate a
very large amount of memory.

If the process has been oom killed, this will cause a lot of memory to
potentially deplete memory reserves.

In the same way that commit 4779280d ("mm: make get_user_pages()
interruptible") aborted for pending SIGKILLs when faulting non-hugetlb
memory, based on the premise of commit 462e00cc ("oom: stop
allocating user memory if TIF_MEMDIE is set"), hugetlb page faults now
terminate when the process has been oom killed.

Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Greg Thelen <gthelen@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 11d83360

mm/hugetlb.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -3277,6 +3277,15 @@ long follow_hugetlb_page(struct mm_struct mm, struct vm_area_struct vma,
		int absent;
		struct page *page;

		/*
		* If we have a pending SIGKILL, don't keep faulting pages and
		* potentially allocating memory.
		*/
		if (unlikely(fatal_signal_pending(current))) {
		remainder = 0;
		break;
		}

		/*
		* Some archs (sparc64, sh*) have multiple pte_ts to
		* each hugepage. We have to make sure we get the