Commit 8024ee2a authored Jul 26, 2016 by Ebru Akagunduz Committed by Linus Torvalds Jul 26, 2016

mm, thp: fix locking inconsistency in collapse_huge_page

After creating revalidate vma function, locking inconsistency occured
due to directing the code path to wrong label.  This patch directs to
correct label and fix the inconsistency.

Related commit that caused inconsistency:
 http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=da4360877094368f6dfe75bbe804b0f0a5d575b0

Link: http://lkml.kernel.org/r/1464956884-4644-1-git-send-email-ebru.akagunduz@gmail.com
Link: http://lkml.kernel.org/r/1466021202-61880-4-git-send-email-kirill.shutemov@linux.intel.com


Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 72695862

mm/huge_memory.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -2483,13 +2483,18 @@ static void collapse_huge_page(struct mm_struct *mm,

		down_read(&mm->mmap_sem);
		result = hugepage_vma_revalidate(mm, address);
		if (result)
		goto out;
		if (result) {
		mem_cgroup_cancel_charge(new_page, memcg, true);
		up_read(&mm->mmap_sem);
		goto out_nolock;
		}

		pmd = mm_find_pmd(mm, address);
		if (!pmd) {
		result = SCAN_PMD_NULL;
		goto out;
		mem_cgroup_cancel_charge(new_page, memcg, true);
		up_read(&mm->mmap_sem);
		goto out_nolock;
		}

		/*
		@@ -2498,8 +2503,9 @@ static void collapse_huge_page(struct mm_struct *mm,
		* Continuing to collapse causes inconsistency.
		*/
		if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) {
		mem_cgroup_cancel_charge(new_page, memcg, true);
		up_read(&mm->mmap_sem);
		goto out;
		goto out_nolock;
		}

		up_read(&mm->mmap_sem);

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