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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: 02bd588e12 ("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
This commit is contained in:
Yeoreum Yun 2025-05-14 17:19:50 +01:00 committed by Suzuki K Poulose
parent 895b12b7d7
commit 53b9e26597
1 changed files with 2 additions and 0 deletions
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2
drivers/hwtracing/coresight/coresight-syscfg.c
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@ -395,6 +395,8 @@ static void cscfg_remove_owned_csdev_configs(struct coresight_device *csdev, voi
if (list_empty(&csdev->config_csdev_list)) if (list_empty(&csdev->config_csdev_list))
return; return;
guard(raw_spinlock_irqsave)(&csdev->cscfg_csdev_lock);
list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) { list_for_each_entry_safe(config_csdev, tmp, &csdev->config_csdev_list, node) {
if (config_csdev->config_desc->load_owner == load_owner) if (config_csdev->config_desc->load_owner == load_owner)
list_del(&config_csdev->node); list_del(&config_csdev->node);