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From: Alison Schofield <alison.schofield@intel.com>
To: Davidlohr Bueso <dave@stgolabs.net>,
	Jonathan Cameron <jonathan.cameron@huawei.com>,
	Dave Jiang <dave.jiang@intel.com>,
	Alison Schofield <alison.schofield@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Dan Williams <dan.j.williams@intel.com>
Cc: linux-cxl@vger.kernel.org
Subject: [PATCH] cxl/test: Assign overflow_err_count from log->nr_overflow
Date: Sat, 15 Nov 2025 17:30:32 -0800	[thread overview]
Message-ID: <20251116013036.1713313-1-alison.schofield@intel.com> (raw)

mock_get_event() uses an uninitialized local variable, nr_overflow, to
populate the overflow_err_count field. That results in incorrect
overflow_err_count values in mocked cxl_overflow trace events, such as
this case where the records are reported as 0 and should be non-zero:

[] cxl_overflow: memdev=mem7 host=cxl_mem.6 serial=7: log=Failure : 0 records from 1763228189130895685 to 1763228193130896180

Fix by using log->nr_overflow and remove the unused local variable.

A follow-up change was considered in cxl_mem_get_records_log() to
confirm that the overflow_err_count is non-zero when the overflow flag
is set [1]. Since the driver has no functional dependency on this
constraint, and a device that violates this specific requirement does
not cause incorrect driver behavior, no validation check is added.

[1] CXL 3.2, Table 8-65 Get Event Records Output Payload

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 tools/testing/cxl/test/mem.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
index d533481672b7..9853bccfa185 100644
--- a/tools/testing/cxl/test/mem.c
+++ b/tools/testing/cxl/test/mem.c
@@ -256,7 +256,6 @@ static int mock_get_event(struct device *dev, struct cxl_mbox_cmd *cmd)
 {
 	struct cxl_get_event_payload *pl;
 	struct mock_event_log *log;
-	u16 nr_overflow;
 	u8 log_type;
 	int i;
 
@@ -299,7 +298,7 @@ static int mock_get_event(struct device *dev, struct cxl_mbox_cmd *cmd)
 		u64 ns;
 
 		pl->flags |= CXL_GET_EVENT_FLAG_OVERFLOW;
-		pl->overflow_err_count = cpu_to_le16(nr_overflow);
+		pl->overflow_err_count = cpu_to_le16(log->nr_overflow);
 		ns = ktime_get_real_ns();
 		ns -= 5000000000; /* 5s ago */
 		pl->first_overflow_timestamp = cpu_to_le64(ns);

base-commit: e9a6fb0bcdd7609be6969112f3fbfcce3b1d4a7c
-- 
2.37.3


             reply	other threads:[~2025-11-16  1:30 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-16  1:30 Alison Schofield [this message]
2025-11-18  2:04 ` [PATCH] cxl/test: Assign overflow_err_count from log->nr_overflow Ira Weiny
2025-11-18 23:10 ` Dave Jiang
2025-11-18 23:34 ` Dave Jiang

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