On Wednesday, September 04, 2013 04:50:01 PM Stephen Boyd wrote: > On 09/04/13 16:55, Rafael J. Wysocki wrote: > > > > Well, I'm not sure when Viresh is going to be back. > > > > Srivatsa, can you please resend this patch with a proper changelog? > > > > I haven't had a chance to try this out yet, but I was just thinking > about this patch. How is it going to work? If one task opens the file > and another task is taking down the CPU wouldn't we deadlock in the > CPU_DOWN notifier waiting for the kobject to be released? Task 1 will > grab the kobject reference and sleep on the hotplug mutex and task 2 > will put the kobject and wait for the completion, but it won't happen. > At least I think that's what would happen. Do you mean the completion in sysfs_deactivate()? Yes, we can deadlock there. Well, I guess the Srivatsa's patch may be salvaged by making it do a "trylock" version of get_online_cpus(), but then I wonder if there's no better way. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
