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authorSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>2022-09-20 14:06:57 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-09-21 21:27:06 +0300
commit68b99e94a4a2db6ba9b31fe0485e057b9354a640 (patch)
treebfb213d2d1919c3500768f36ed8ecab9d6a62962 /drivers/thermal
parente9a7c526c29b0ae60c888b335bd6cf6e2ee80154 (diff)
downloadlinux-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.c6
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);