Messages in this thread | | | Date | Tue, 16 Nov 2021 16:32:52 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH v1] hugetlb, userfaultfd: Fix reservation restore on userfaultfd error |
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On Tue, 16 Nov 2021 15:57:32 -0800 Mina Almasry <almasrymina@google.com> wrote:
> Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we > bail out using "goto out_release_unlock;" in the cases where idx >= > size, or !huge_pte_none(), the code will detect that new_pagecache_page > == false, and so call restore_reserve_on_error(). > In this case I see restore_reserve_on_error() delete the reservation, > and the following call to remove_inode_hugepages() will increment > h->resv_hugepages causing a 100% reproducible leak. > > We should treat the is_continue case similar to adding a page into the > pagecache and set new_pagecache_page to true, to indicate that there is > no reservation to restore on the error path, and we need not call > restore_reserve_on_error(). > > Cc: Wei Xu <weixugc@google.com> > > Fixes: c7b1850dfb41 ("hugetlb: don't pass page cache pages to restore_reserve_on_error")
I added cc:stable to this.
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