https://github.com/torvalds/linux
Revision 9cc3a5bd40067b9a0fbd49199d0780463fc2140f authored by Naoya Horiguchi on 17 April 2013, 22:58:30 UTC, committed by Linus Torvalds on 17 April 2013, 23:10:44 UTC
With applying the previous patch "hugetlbfs: stop setting VM_DONTDUMP in initializing vma(VM_HUGETLB)" to reenable hugepage coredump, if a memory error happens on a hugepage and the affected processes try to access the error hugepage, we hit VM_BUG_ON(atomic_read(&page->_count) <= 0) in get_page(). The reason for this bug is that coredump-related code doesn't recognise "hugepage hwpoison entry" with which a pmd entry is replaced when a memory error occurs on a hugepage. In other words, physical address information is stored in different bit layout between hugepage hwpoison entry and pmd entry, so follow_hugetlb_page() which is called in get_dump_page() returns a wrong page from a given address. The expected behavior is like this: absent is_swap_pte FOLL_DUMP Expected behavior ------------------------------------------------------------------- true false false hugetlb_fault false true false hugetlb_fault false false false return page true false true skip page (to avoid allocation) false true true hugetlb_fault false false true return page With this patch, we can call hugetlb_fault() and take proper actions (we wait for migration entries, fail with VM_FAULT_HWPOISON_LARGE for hwpoisoned entries,) and as the result we can dump all hugepages except for hwpoisoned ones. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> [2.6.34+?] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: 9cc3a5bd40067b9a0fbd49199d0780463fc2140f authored by Naoya Horiguchi on 17 April 2013, 22:58:30 UTC
hugetlbfs: add swap entry check in follow_hugetlb_page()
hugetlbfs: add swap entry check in follow_hugetlb_page()
Tip revision: 9cc3a5b
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crypto | ||
drivers | ||
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fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
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net | ||
samples | ||
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sound | ||
tools | ||
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.gitignore | -rw-r--r-- | 1.1 KB |
.mailmap | -rw-r--r-- | 4.4 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 93.0 KB |
Kbuild | -rw-r--r-- | 2.5 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 244.0 KB |
Makefile | -rw-r--r-- | 47.0 KB |
README | -rw-r--r-- | 18.3 KB |
REPORTING-BUGS | -rw-r--r-- | 3.3 KB |
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