diff options
| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2022-09-20 04:06:57 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-26 13:25:44 +0200 |
| commit | 513943bf879d45005213e6f5cfb7d9e9943f589f (patch) | |
| tree | c391f96febb5ef1325e6c3a84143c88e6d5815c4 | |
| parent | 708b9abe1b4a2f050a483db4b7edfc446b13df1f (diff) | |
thermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash
[ Upstream commit 68b99e94a4a2db6ba9b31fe0485e057b9354a640 ]
When CPU 0 is offline and intel_powerclamp is used to inject
idle, it generates kernel BUG:
BUG: using smp_processor_id() in preemptible [00000000] code: bash/15687
caller is debug_smp_processor_id+0x17/0x20
CPU: 4 PID: 15687 Comm: bash Not tainted 5.19.0-rc7+ #57
Call Trace:
<TASK>
dump_stack_lvl+0x49/0x63
dump_stack+0x10/0x16
check_preemption_disabled+0xdd/0xe0
debug_smp_processor_id+0x17/0x20
powerclamp_set_cur_state+0x7f/0xf9 [intel_powerclamp]
...
...
Here CPU 0 is the control CPU by default and changed to the current CPU,
if CPU 0 offlined. This check has to be performed under cpus_read_lock(),
hence the above warning.
Use get_cpu() instead of smp_processor_id() to avoid this BUG.
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/thermal/intel/intel_powerclamp.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/thermal/intel/intel_powerclamp.c b/drivers/thermal/intel/intel_powerclamp.c index b0eb5ece9243..14381f7587ff 100644 --- a/drivers/thermal/intel/intel_powerclamp.c +++ b/drivers/thermal/intel/intel_powerclamp.c @@ -532,8 +532,10 @@ static int start_power_clamp(void) /* prefer BSP */ control_cpu = 0; - if (!cpu_online(control_cpu)) - control_cpu = smp_processor_id(); + if (!cpu_online(control_cpu)) { + control_cpu = get_cpu(); + put_cpu(); + } clamping = true; schedule_delayed_work(&poll_pkg_cstate_work, 0); |