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    SubjectRe: [PATCH V3] MMC: core: cap MMC card timeouts at UINT_MAX
    On 01/06/12 16:20, Torne (Richard Coles) wrote:
    > From: "Torne (Richard Coles)" <torne@google.com>
    >
    > MMC CSD info can specify very large, ridiculous timeouts, big enough to
    > overflow timeout_ns. This can result in the card timing out on every
    > operation because the wrapped timeout value is far too small.
    >
    > Fix the overflow by capping the result at UINT_MAX. Cards specifying
    > longer timeouts are almost certainly insane, and host controllers
    > generally cannot support timeouts that long in any case.
    >
    > Signed-off-by: Torne (Richard Coles) <torne@google.com>
    > ---
    > drivers/mmc/core/core.c | 11 ++++++++++-
    > 1 files changed, 10 insertions(+), 1 deletions(-)
    >
    > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
    > index 0b6141d..74ec3d4 100644
    > --- a/drivers/mmc/core/core.c
    > +++ b/drivers/mmc/core/core.c
    > @@ -512,7 +512,16 @@ void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card)
    > if (data->flags & MMC_DATA_WRITE)
    > mult <<= card->csd.r2w_factor;
    >
    > - data->timeout_ns = card->csd.tacc_ns * mult;
    > + /*
    > + * The timeout in nanoseconds may overflow with some cards. Cap it at
    > + * UINT_MAX to avoid the overflow; host controllers cannot generally
    > + * generate timeouts that long anyway.
    > + */
    > + if (card->csd.tacc_ns <= UINT_MAX / mult)
    > + data->timeout_ns = card->csd.tacc_ns * mult;
    > + else
    > + data->timeout_ns = UINT_MAX;
    > +
    > data->timeout_clks = card->csd.tacc_clks * mult;
    >
    > /*

    Acked-by: Adrian Hunter <adrian.hunter@intel.com>


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