From: Andrew Morton <akpm@linux-foundation.org>
To: Mina Almasry <almasrymina@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
Wei Xu <weixugc@google.com>,
James Houghton <jthoughton@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] hugetlb, userfaultfd: Fix reservation restore on userfaultfd error
Date: Tue, 16 Nov 2021 16:32:52 -0800 [thread overview]
Message-ID: <20211116163252.0d4643fc0593b8fcaf7aa4ac@linux-foundation.org> (raw)
In-Reply-To: <20211116235733.3774702-1-almasrymina@google.com>
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.
next prev parent reply other threads:[~2021-11-17 0:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-16 23:57 Mina Almasry
2021-11-17 0:00 ` Mina Almasry
2021-11-17 0:32 ` Andrew Morton [this message]
2021-11-17 0:58 ` Mike Kravetz
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