Messages in this thread Patch in this message | | | From | "Torne (Richard Coles)" <> | Subject | [PATCH V3] MMC: core: cap MMC card timeouts at UINT_MAX | Date | Fri, 1 Jun 2012 14:20:15 +0100 |
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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; /* -- 1.7.7.3
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