Messages in this thread | | | Date | Wed, 18 Jan 2017 20:04:45 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH] mm/mempolicy.c: do not put mempolicy before using its nodemask |
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On Wed, Jan 18, 2017 at 03:11:24PM +0100, Vlastimil Babka wrote: > Since commit be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to > alloc_pages_vma") alloc_pages_vma() can potentially free a mempolicy by > mpol_cond_put() before accessing the embedded nodemask by > __alloc_pages_nodemask(). The commit log says it's so "we can use a single > exit path within the function" but that's clearly wrong. We can still do that > when doing mpol_cond_put() after the allocation attempt. > > Make sure the mempolicy is not freed prematurely, otherwise > __alloc_pages_nodemask() can end up using a bogus nodemask, which could lead > e.g. to premature OOM. > > Fixes: be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to alloc_pages_vma") > Signed-off-by: Vlastimil Babka <vbabka@suse.cz> > Cc: stable@vger.kernel.org > Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > Cc: David Rientjes <rientjes@google.com> > Cc: Andrea Arcangeli <aarcange@redhat.com>
Looks good to me.
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
-- Kirill A. Shutemov
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