mmc: tmio: prevent endless loop in tmio_mmc_set_clock()
authorSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Thu, 18 Sep 2014 19:33:49 +0000 (23:33 +0400)
committerUlf Hansson <ulf.hansson@linaro.org>
Fri, 19 Sep 2014 18:43:09 +0000 (20:43 +0200)
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 <sergei.shtylyov@cogentembedded.com>
Acked-by: Ian Molton <ian.molton@codethink.co.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
drivers/mmc/host/tmio_mmc_pio.c

index 692e578..e487ba4 100644 (file)
@@ -1121,6 +1121,15 @@ int tmio_mmc_host_probe(struct tmio_mmc_host **host,
                mmc->f_min = mmc->f_max / 512;
        }
 
+       /*
+        * 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.