James Bottomley <[email protected]> writes: > On Thu, 2015-09-10 at 16:08 -0700, Andrew Morton wrote: >> On Fri, 4 Sep 2015 14:56:33 +0200 Vitaly Kuznetsov <[email protected]> >> 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.
Sorry for delayed reply, I was traveling. Please change string_get_size(1, 512, STRING_UNITS_2, buf, sizeof(buf)); to string_get_size(1, 512, STRING_UNITS_10, buf, sizeof(buf)); in your test.c program to see the issue, it will enter the infinite loop as well. Regardless to Hyper-V I think such library function shouldn't do such nasty things (but I'll try to investigate why such small size was reported). -- Vitaly -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
