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| author | Mina Almasry <almasrymina@google.com> | 2021-11-20 03:43:43 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-25 11:48:42 +0300 |
| commit | b5069d44e2fbc4a9093d005b3ef0949add3dd27e (patch) | |
| tree | fc1bc19fb1d661e66c98630d711d1a2ae20535e7 /mm/highmem.c | |
| parent | 11138d734963e089a3a2797f2d761ad25efdbb19 (diff) | |
| download | linux-b5069d44e2fbc4a9093d005b3ef0949add3dd27e.tar.xz | |
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
commit cc30042df6fcc82ea18acf0dace831503e60a0b7 upstream.
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(). Rename new_pagecache_page to
page_in_pagecache to make that clear.
Link: https://lkml.kernel.org/r/20211117193825.378528-1-almasrymina@google.com
Fixes: c7b1850dfb41 ("hugetlb: don't pass page cache pages to restore_reserve_on_error")
Signed-off-by: Mina Almasry <almasrymina@google.com>
Reported-by: James Houghton <jthoughton@google.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/highmem.c')
0 files changed, 0 insertions, 0 deletions