[PATCH v2 12/28] coresight: sysfs: Validate CPU online status for per-CPU sources

[Leo Yan]

The current SysFS flow first enables the links and sink, then rolls back
to disable them if the source fails to enable. This failure can occur if
the associated CPU is offline, which causes the SMP call to fail.

Validate whether the associated CPU is online for a per-CPU tracer. If
the CPU is offline, return -ENODEV and bail out.

Signed-off-by: Leo Yan <leo.yan at arm.com>
---
 drivers/hwtracing/coresight/coresight-sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index feadaf065b5318c8426aa53420b8e5f67a258683..14ee15297b98115122068cbe932f0b2ce004b77e 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -161,6 +161,9 @@ static int coresight_validate_source_sysfs(struct coresight_device *csdev,
 		return -EINVAL;
 	}
 
+	if (coresight_is_percpu_source(csdev) && !cpu_online(csdev->cpu))
+		return -ENODEV;
+
 	return 0;
 }
 

-- 
2.34.1