On Mon, 16 Dec 2024 at 11:50, Yeoreum Yun yeoreum.yun@arm.com wrote:
coresight_device->cscfg_csdev_lock can be held during __schedule() by perf_event_task_sched_out()/in().
Since coresight->cscfg_csdev_lock type is spinlock_t and perf_event_task_sched_out()/in() is called after acquiring rq_lock, which is raw_spinlock_t (an unsleepable lock), this poses an issue in PREEMPT_RT kernel where spinlock_t is sleepable.
To address this, change type of coresight_device->cscfg_csdev_lock from spinlock_t to raw_spinlock_t.
Signed-off-by: Yeoreum Yun yeoreum.yun@arm.com
.../hwtracing/coresight/coresight-syscfg.c | 26 +++++++++---------- include/linux/coresight.h | 2 +- 2 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c index 11138a9762b0..a70c1454b410 100644 --- a/drivers/hwtracing/coresight/coresight-syscfg.c +++ b/drivers/hwtracing/coresight/coresight-syscfg.c @@ -89,9 +89,9 @@ static int cscfg_add_csdev_cfg(struct coresight_device *csdev, } /* if matched features, add config to device.*/ if (config_csdev) {
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); list_add(&config_csdev->node, &csdev->config_csdev_list);
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); } return 0;@@ -194,9 +194,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
/* add to internal csdev feature list & initialise using reset call */ cscfg_reset_feat(feat_csdev);
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); list_add(&feat_csdev->node, &csdev->feature_csdev_list);
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); return 0;} @@ -765,7 +765,7 @@ static int cscfg_list_add_csdev(struct coresight_device *csdev,
INIT_LIST_HEAD(&csdev->feature_csdev_list); INIT_LIST_HEAD(&csdev->config_csdev_list);
spin_lock_init(&csdev->cscfg_csdev_lock);
raw_spin_lock_init(&csdev->cscfg_csdev_lock); return 0;} @@ -855,7 +855,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev) struct cscfg_feature_csdev *feat_csdev; unsigned long flags;
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); if (list_empty(&csdev->feature_csdev_list)) goto unlock_exit;@@ -863,7 +863,7 @@ void cscfg_csdev_reset_feats(struct coresight_device *csdev) cscfg_reset_feat(feat_csdev);
unlock_exit:
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);} EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
@@ -1059,7 +1059,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, * Look for matching configuration - set the active configuration * context if found. */
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) { config_desc = config_csdev_item->config_desc; if ((atomic_read(&config_desc->active_cnt)) &&@@ -1069,7 +1069,7 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, break; } }
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); /* * If found, attempt to enable@@ -1090,12 +1090,12 @@ int cscfg_csdev_enable_active_config(struct coresight_device *csdev, * * Set enabled if OK, err if not. */
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); if (csdev->active_cscfg_ctxt) config_csdev_active->enabled = true; else err = -EBUSY;
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); } } return err;@@ -1124,7 +1124,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev) * If it was not enabled, we have no work to do, otherwise mark as disabled. * Clear the active config pointer. */
spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
raw_spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags); config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt; if (config_csdev) { if (!config_csdev->enabled)@@ -1133,7 +1133,7 @@ void cscfg_csdev_disable_active_config(struct coresight_device *csdev) config_csdev->enabled = false; } csdev->active_cscfg_ctxt = NULL;
spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
raw_spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags); /* true if there was an enabled active config */ if (config_csdev)diff --git a/include/linux/coresight.h b/include/linux/coresight.h index c13342594278..924b58c343b3 100644 --- a/include/linux/coresight.h +++ b/include/linux/coresight.h @@ -296,7 +296,7 @@ struct coresight_device { /* system configuration and feature lists */ struct list_head feature_csdev_list; struct list_head config_csdev_list;
spinlock_t cscfg_csdev_lock;
raw_spinlock_t cscfg_csdev_lock; void *active_cscfg_ctxt;};
-- LEVI:{C3F47F37-75D8-414A-A8BA-3980EC8A46D7}
Reviewed-by: Mike Leach mike.leach@linaro.org
-- Mike Leach Principal Engineer, ARM Ltd. Manchester Design Centre. UK
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Mike Leach