[PATCH] cxl/trace: Initialize cxl_poison region name to NULL

From: alison.schofield@intel.com
To: Davidlohr Bueso <dave@stgolabs.net>,
	Jonathan Cameron <jonathan.cameron@huawei.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Dan Williams <dan.j.williams@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>, linux-cxl@vger.kernel.org
Subject: [PATCH] cxl/trace: Initialize cxl_poison region name to NULL
Date: Wed, 13 Mar 2024 21:43:01 -0700	[thread overview]
Message-ID: <20240314044301.2108650-1-alison.schofield@intel.com> (raw)

From: Alison Schofield <alison.schofield@intel.com>

The TP_STRUCT__entry that gets assigned the region name, or an
empty string if no region is present, is erroneously initialized
to the cxl_region pointer. It needs to be initialized to NULL
otherwise its length is wrong and garbage chars can appear in
the kernel trace output: /sys/kernel/tracing/trace

Impact is that tooling depending on that trace data can miss
picking up a valid event when searching by region name. The
TP_printk() output, if enabled, does emit the correct region
names in the dmesg log.

This was found during testing of the cxl-list option to report
media-errors for a region.

Fixes: ddf49d57b841 ("cxl/trace: Add TRACE support for CXL media-error records")
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 drivers/cxl/core/trace.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
index bdf117a33744..bc5ca4d530d1 100644
--- a/drivers/cxl/core/trace.h
+++ b/drivers/cxl/core/trace.h
@@ -657,7 +657,7 @@ TRACE_EVENT(cxl_poison,
 		__string(host, dev_name(cxlmd->dev.parent))
 		__field(u64, serial)
 		__field(u8, trace_type)
-		__string(region, region)
+		__string(region, NULL)
 		__field(u64, overflow_ts)
 		__field(u64, hpa)
 		__field(u64, dpa)

base-commit: e8f897f4afef0031fe618a8e94127a0934896aba
-- 
2.37.3

