From: Leo Yan <leo.yan@arm.com>
Date: Fri, 15 May 2026 20:08:35 +0000 (+0100)
Subject: coresight: sysfs: Validate CPU online status for per-CPU sources
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=a5dd853fb7774c9543aed272a8614c15ebce3173;p=thirdparty%2Fkernel%2Flinux.git

coresight: sysfs: Validate CPU online status for per-CPU sources

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.

Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-28-f88c4a3ecfe9@arm.com
---

diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index 80b6b634a70d..4b010f8bc4c0 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -168,6 +168,9 @@ 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;
 }