Commit f1a18a105 "Thermal: CPU Package temperature thermal" had code that did a get_online_cpus(), run a loop and then do a put_online_cpus(). The problem is that the loop had an error exit that would skip the put_online_cpus() part.
In the error exit part of the function, it also did a get_online_cpus(), run a loop and then put_online_cpus(). The only way to get to the error exit part is with get_online_cpus() already performed. If this error condition is hit, the system will be prevented from taking CPUs offline. The process taking the CPU offline will lock up hard. Removing the get_online_cpus() removes the lockup as the hotplug CPU refcount is back to zero. This was bisected with ktest. Signed-off-by: Steven Rostedt <[email protected]> diff --git a/drivers/thermal/x86_pkg_temp_thermal.c b/drivers/thermal/x86_pkg_temp_thermal.c index 5de56f6..d47624c 100644 --- a/drivers/thermal/x86_pkg_temp_thermal.c +++ b/drivers/thermal/x86_pkg_temp_thermal.c @@ -592,7 +592,6 @@ static int __init pkg_temp_thermal_init(void) return 0; err_ret: - get_online_cpus(); for_each_online_cpu(i) put_core_offline(i); put_online_cpus(); -- 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/
