| From | Greg Kroah-Hartman <> | Subject | [ 075/110] mm: Fix generic hugetlb pte check return type. | Date | Fri, 11 Oct 2013 12:38:55 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: David Miller <davem@davemloft.net>
[ Upstream commit 26794942461f438a6bc725ec7294b08a6bd782c4 ]
The include/asm-generic/hugetlb.h stubs that just vector huge_pte_*() calls to the pte_*() implementations won't work in certain situations.
x86 and sparc, for example, return "unsigned long" from the bit checks, and just go "return pte_val(pte) & PTE_BIT_FOO;"
But since huge_pte_*() returns 'int', if any high bits on 64-bit are relevant, they get chopped off.
The net effect is that we can loop forever trying to COW a huge page, because the huge_pte_write() check signals false all the time.
Reported-by: Gurudas Pai <gurudas.pai@oracle.com> Tested-by: Gurudas Pai <gurudas.pai@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- include/asm-generic/hugetlb.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/asm-generic/hugetlb.h +++ b/include/asm-generic/hugetlb.h @@ -6,12 +6,12 @@ static inline pte_t mk_huge_pte(struct p return mk_pte(page, pgprot); } -static inline int huge_pte_write(pte_t pte) +static inline unsigned long huge_pte_write(pte_t pte) { return pte_write(pte); } -static inline int huge_pte_dirty(pte_t pte) +static inline unsigned long huge_pte_dirty(pte_t pte) { return pte_dirty(pte); }
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