[lkml]   [2020]   [Feb]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH -next] power/qos: fix a data race in pm_qos_*_value

> On Feb 23, 2020, at 7:12 PM, Rafael J. Wysocki <> wrote:
> It may be a bug under certain conditions, but you don't mention what
> conditions they are. Reporting it as a general bug is not accurate at
> the very least.

Could we rule out load tearing, store tearing and reload of global_req in cpuidle_governor_latency() for all compilers and architectures which could introduce logic bugs?

int global_req = cpu_latency_qos_limit();

if (device_req > global_req)
device_req = global_req;

If under register pressure, the compiler might get ride of the tmp variable, i.e.,

If (device_req > cpu_latency_qos_limit())
—-> race with the writer.
device_req = cpu_latency_qos_limit();

 \ /
  Last update: 2020-02-24 02:02    [W:0.086 / U:23.124 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site