diff options
| author | Eric Biggers <ebiggers@google.com> | 2018-12-28 11:34:43 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 23:11:47 +0300 |
| commit | ca880420665dbc8beec3693bee9f5eccb89de4a6 (patch) | |
| tree | 7255c489175110780706a7eaf04fe8f0f34611b5 /mm/page_alloc.c | |
| parent | 66f71da9dd38af17dc17209cdde7987d4679a699 (diff) | |
| download | linux-ca880420665dbc8beec3693bee9f5eccb89de4a6.tar.xz | |
userfaultfd: convert userfaultfd_ctx::refcount to refcount_t
Reference counters should use refcount_t rather than atomic_t, since the
refcount_t implementation can prevent overflows, reducing the
exploitability of reference leak bugs. userfaultfd_ctx::refcount is a
reference counter with the usual semantics, so convert it to refcount_t.
Note: I replaced the BUG() on incrementing a 0 refcount with just
refcount_inc(), since part of the semantics of refcount_t is that that
incrementing a 0 refcount is not allowed; with CONFIG_REFCOUNT_FULL,
refcount_inc() already checks for it and warns.
Link: http://lkml.kernel.org/r/20181115003916.63381-1-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
0 files changed, 0 insertions, 0 deletions