Re: [PATCH v2] cxl/trace: Properly initialize cxl_poison region name

From: Ira Weiny <ira.weiny@intel.com>
To: <alison.schofield@intel.com>, 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>,
	Steve Rostedt <rostedt@goodmis.org>
Cc: Alison Schofield <alison.schofield@intel.com>,
	<linux-cxl@vger.kernel.org>
Subject: Re: [PATCH v2] cxl/trace: Properly initialize cxl_poison region name
Date: Thu, 14 Mar 2024 13:51:57 -0700	[thread overview]
Message-ID: <65f3636da691e_22141294d7@iweiny-mobl.notmuch> (raw)
In-Reply-To: <20240314201217.2112644-1-alison.schofield@intel.com>

alison.schofield@ wrote:
> 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 properly initialized
> otherwise it's length is wrong and garbage chars can appear in
> the kernel trace output: /sys/kernel/tracing/trace
> 
> The bad initialization was due in part to a naming conflict with
> the parameter: struct cxl_region *region. The field 'region' is
> already exposed externally as the region name, so changing that
> to something logical, like 'region_name' is not an option. Instead
> rename the internal only struct cxl_region to the commonly used
> 'cxlr'.
> 
> 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.
> 

Reviewed-by: Ira Weiny <ira.weiny@intel.com>