Skip to content
Commit 50c668d6 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Revert "cpumask: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write"

This reverts commit 7503bfba

.

Dieter Ries reported bootup soft-hangs and bisected it back to
this commit, and reverting this commit gave him a working system.

The commit introduces work_on_cpu() use into the cpufreq code,
but that is subtly problematic from a lock hierarchy POV: the
hotplug-cpu lock is an highlevel lock that is taken before
lowlevel locks, and in this codepath we are called with the
policy lock taken.

Dieter did not have lockdep enabled so we dont have a nice stack
trace proof for this, but using work_on_cpu() in such a lowlevel
place certainly looks wrong, so we revert the patch.

work_on_cpu() needs to be reworked to be more generally usable.

Reported-by: default avatarDieter Ries <clip2@gmx.de>
Tested-by: default avatarDieter Ries <clip2@gmx.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 2bc13797
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment