Messages in this thread | | | Subject | Re: [PATCH] lib/string_helpers.c: fix infinite loop in string_get_size() | From | Andy Shevchenko <> | Date | Mon, 14 Sep 2015 17:33:41 +0300 |
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On Mon, 2015-09-14 at 14:43 +0200, Vitaly Kuznetsov wrote: > Andy Shevchenko <andriy.shevchenko@linux.intel.com> writes: > > > On Fri, 2015-09-11 at 18:31 +0000, James Bottomley wrote: > > > On Thu, 2015-09-10 at 16:08 -0700, Andrew Morton wrote: > > > > On Fri, 4 Sep 2015 14:56:33 +0200 Vitaly Kuznetsov < > > > > vkuznets@redhat.com> wrote: > > > > > > > > > string_get_size(1, 512, 0, ..., ...) call results in an > > > > > infinite > > > > > loop. The > > > > > problem is that if size == 0 when we start calculating sf_cap > > > > > > > > > > this loop > > > > > will never end. > > > > > > > > > > The caller causing the issue is sd_read_capacity(), the > > > > > problem > > > > > was noticed > > > > > on Hyper-V. > > > > > > > > When fixing bugs, please provide enough info for others to be > > > > able > > > > to > > > > understand which kernel version(s) need the fix. In this case: > > > > > > > > what > > > > end-user action triggers this bug? (iow, how does sdkp > > > > ->capacity > > > > become zero?) > > > > > > Any more details. The attached programme, which is cut straight > > > out > > > of > > > the algorithm in string_helpers.c and modified for a C > > > environment > > > slightly (only in do_div and the typedefs) produces this > > > > > > hello > > > STRING IS 512 B > > > > > > With your input, so I don't think the problem is where you think > > > it > > > is. > > > > > > James > > > > > > > Vitaly, it might make sense to extend test-string_helpers.c to what > > you > > are trying to do right. > > The issue is that string_get_size() enters an infinite loop on some > inputs so if we add a test for such inputs we'll hang our kernel... >
I didn't see a problem to add this test case. Since test module is dedicated for that (tests).
-- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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