From mboxrd@z Thu Jan 1 00:00:00 1970 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 Message-ID: <1338556815-26487-1-git-send-email-torne@google.com> References: Return-path: Received: from mail-gh0-f202.google.com ([209.85.160.202]:42817 "EHLO mail-gh0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759678Ab2FANUW (ORCPT ); Fri, 1 Jun 2012 09:20:22 -0400 Received: by ghbz15 with SMTP id z15so206004ghb.1 for ; Fri, 01 Jun 2012 06:20:22 -0700 (PDT) In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: cjb@laptop.org Cc: linus.walleij@linaro.org, jh80.chung@samsung.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, ben@decadent.org.uk, "Torne (Richard Coles)" From: "Torne (Richard Coles)" 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) --- 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