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    SubjectRe: [PATCH 4/8] rhashtable: fix race in nested_table_alloc()
    On Fri, May 04, 2018 at 01:54:14PM +1000, NeilBrown wrote:
    > If two threads run nested_table_alloc() at the same time
    > they could both allocate a new table.
    > Best case is that one of them will never be freed, leaking memory.
    > Worst case is hat entry get stored there before it leaks,
    > and the are lost from the table.
    >
    > So use cmpxchg to detect the race and free the unused table.
    >
    > Fixes: da20420f83ea ("rhashtable: Add nested tables")
    > Cc: stable@vger.kernel.org # 4.11+
    > Signed-off-by: NeilBrown <neilb@suse.com>

    What about the spinlock that's meant to be held around this
    operation?

    Cheers,
    --
    Email: Herbert Xu <herbert@gondor.apana.org.au>
    Home Page: http://gondor.apana.org.au/~herbert/
    PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

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