From: Andrea Arcangeli Date: Wed, 22 Sep 2010 20:05:12 +0000 (-0700) Subject: rmap: fix walk during fork X-Git-Tag: v2.6.36-rc6~58 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;ds=sidebyside;h=a247c3a97a0216b18a46243eda26081f1928ec37;p=pandora-kernel.git rmap: fix walk during fork The below bug in fork led to the rmap walk finding the parent huge-pmd twice instead of just once, because the anon_vma_chain objects of the child vma still point to the vma->vm_mm of the parent. The patch fixes it by making the rmap walk accurate during fork. It's not a big deal normally but it worth being accurate considering the cost is the same. Signed-off-by: Andrea Arcangeli Acked-by: Johannes Weiner Acked-by: Rik van Riel Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/fork.c b/kernel/fork.c index b7e9d60a675d..c445f8cc408d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -356,10 +356,10 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) if (IS_ERR(pol)) goto fail_nomem_policy; vma_set_policy(tmp, pol); + tmp->vm_mm = mm; if (anon_vma_fork(tmp, mpnt)) goto fail_nomem_anon_vma_fork; tmp->vm_flags &= ~VM_LOCKED; - tmp->vm_mm = mm; tmp->vm_next = tmp->vm_prev = NULL; file = tmp->vm_file; if (file) {