https://github.com/torvalds/linux
Revision 0d777df5d8953293be090d9ab5a355db893e8357 authored by Naoya Horiguchi on 11 December 2015, 21:40:49 UTC, committed by Linus Torvalds on 12 December 2015, 18:15:34 UTC
Currently at the beginning of hugetlb_fault(), we call huge_pte_offset() and check whether the obtained *ptep is a migration/hwpoison entry or not. And if not, then we get to call huge_pte_alloc(). This is racy because the *ptep could turn into migration/hwpoison entry after the huge_pte_offset() check. This race results in BUG_ON in huge_pte_alloc(). We don't have to call huge_pte_alloc() when the huge_pte_offset() returns non-NULL, so let's fix this bug with moving the code into else block. Note that the *ptep could turn into a migration/hwpoison entry after this block, but that's not a problem because we have another !pte_present check later (we never go into hugetlb_no_page() in that case.) Fixes: 290408d4a250 ("hugetlb: hugepage migration core") Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: <stable@vger.kernel.org> [2.6.36+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: 0d777df5d8953293be090d9ab5a355db893e8357 authored by Naoya Horiguchi on 11 December 2015, 21:40:49 UTC
mm: hugetlb: call huge_pte_alloc() only if ptep is null
mm: hugetlb: call huge_pte_alloc() only if ptep is null
Tip revision: 0d777df
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crypto | ||
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kernel | ||
lib | ||
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net | ||
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COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 94.9 KB |
Kbuild | -rw-r--r-- | 2.6 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 328.5 KB |
Makefile | -rw-r--r-- | 53.5 KB |
README | -rw-r--r-- | 18.2 KB |
REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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