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| author | Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> | 2022-09-20 14:06:57 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-09-21 21:27:06 +0300 |
| commit | 68b99e94a4a2db6ba9b31fe0485e057b9354a640 (patch) | |
| tree | bfb213d2d1919c3500768f36ed8ecab9d6a62962 /drivers/thermal | |
| parent | e9a7c526c29b0ae60c888b335bd6cf6e2ee80154 (diff) | |
| download | linux-68b99e94a4a2db6ba9b31fe0485e057b9354a640.tar.xz | |
thermal: intel_powerclamp: Use get_cpu() instead of smp_processor_id() to avoid crash
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>
Diffstat (limited to 'drivers/thermal')
| -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 c841ab37e7c6..46cd799af148 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); |