On Mon, Oct 28, 2013 at 11:05:06AM +0100, Alexander Gordeev wrote: > Function steal_tags() might miss a bit in cpus_have_tags due to > unsynchronized access from percpu_ida_free(). As result, function > percpu_ida_alloc() might enter unwakable sleep. This update adds > memory barriers to prevent the described scenario. > > In fact, accesses to cpus_have_tags are fenced by prepare_to_wait() > and wake_up() calls at the moment and the aforementioned sequence > does not appear could hit. Nevertheless, explicit memory barriers > still seem justifiable.
Good catch! Acked-by: Kent Overstreet <[email protected]> -- 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/
