coresight: holding cscfg_csdev_lock while removing cscfg from csdev

There'll be possible race scenario for coresight config:

CPU0                                          CPU1
(perf enable)                                 load module
                                              cscfg_load_config_sets()
                                              activate config. // sysfs
                                              (sys_active_cnt == 1)
...
cscfg_csdev_enable_active_config()
  lock(csdev->cscfg_csdev_lock)
                                              deactivate config // sysfs
                                              (sys_activec_cnt == 0)
                                              cscfg_unload_config_sets()
  <iterating config_csdev_list>               cscfg_remove_owned_csdev_configs()
  // here load config activate by CPU1
  unlock(csdev->cscfg_csdev_lock)

iterating config_csdev_list could be raced with config_csdev_list's
entry delete.

To resolve this race , hold csdev->cscfg_csdev_lock() while
cscfg_remove_owned_csdev_configs()

Fixes: 02bd588e12df ("coresight: configuration: Update API to permit dynamic load/unload")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250514161951.3427590-3-yeoreum.yun@arm.com

diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index a70c1454b4106c8847e85b8dae981608b762c030..23017612f2eae03c2146cf577257ced5e7d3c002 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -395,6 +395,8 @@ static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, voi
        if (list_empty(&csdev->config_csdev_list))
                return;
 
+  guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock);
+
        list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) {
                if (config_csdev->config_desc->load_owner == load_owner)
                        list_del(&config_csdev->node);