Messages in this thread | | | Date | Tue, 16 Jul 2013 11:34:06 -0700 | From | Srinivas Pandruvada <> | Subject | Re: [PATCH] Thermal: Fix lockup of cpu_down() |
| |
On 07/16/2013 11:02 AM, Steven Rostedt wrote: > 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 <rostedt@goodmis.org> > > 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(); > Agreed. >
| |