From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: [PATCH v4] tmio_mmc_pio: prevent endless loop in tmio_mmc_set_clock() Date: Thu, 18 Sep 2014 23:33:49 +0400 Message-ID: <10228473.uOqbQ0oioV@wasted.cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mail-we0-f170.google.com ([74.125.82.170]:44989 "EHLO mail-we0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756755AbaIRUc7 (ORCPT ); Thu, 18 Sep 2014 16:32:59 -0400 Received: by mail-we0-f170.google.com with SMTP id u57so1526082wes.15 for ; Thu, 18 Sep 2014 13:32:58 -0700 (PDT) Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: linux-mmc@vger.kernel.org, ian.molton@codethink.co.uk, chris@printf.net, ulf.hansson@linaro.org Cc: linux-sh@vger.kernel.org I spent a couple of days with the driver just hanging due to me forgetting to specify the external crystal frequency, so that clk_get_rate() returned 0 and thus the loop in tmio_mmc_set_clock() never ended. I don't think that's an acceptable behavior, so I suggest that the minimum frequency is checked for 0 in tmio_mmc_host_probe(). Signed-off-by: Sergei Shtylyov Acked-by: Ian Molton Cc: stable@vger.kernel.org --- The patch is against Ulf Hansson's 'mmc.git' repo's 'next' branch. Changes in version 4: - rebased to the 'next' branch, resolving reject; - added Ian Molton's ACK. Changes in version 3: - added Cc: stable. Changes in version 2: - fixed grammar in the changelog. drivers/mmc/host/tmio_mmc_pio.c | 9 +++++++++ 1 file changed, 9 insertions(+) Index: mmc/drivers/mmc/host/tmio_mmc_pio.c =================================================================== --- mmc.orig/drivers/mmc/host/tmio_mmc_pio.c +++ mmc/drivers/mmc/host/tmio_mmc_pio.c @@ -1091,6 +1091,15 @@ int tmio_mmc_host_probe(struct tmio_mmc_ } /* + * Check the sanity of mmc->f_min to prevent tmio_mmc_set_clock() from + * looping forever... + */ + if (mmc->f_min == 0) { + ret = -EINVAL; + goto host_free; + } + + /* * While using internal tmio hardware logic for card detection, we need * to ensure it stays powered for it to work. */