linux-kernel - Re: "invalid agent type: 1" in acpi/ghes, cper: Recognize and cache CXL Protocol errors

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ef9c9418-2def-484a-89fb-b0235391ad83@linux.intel.com>
Date: Mon, 28 Jul 2025 22:41:54 -0700
From: Marc Herbert <marc.herbert@...ux.intel.com>
To: "Koralahalli Channabasappa, Smita"
 <Smita.KoralahalliChannabasappa@....com>, linux-efi@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-cxl@...r.kernel.org
Cc: Ard Biesheuvel <ardb@...nel.org>,
 Alison Schofield <alison.schofield@...el.com>,
 Vishal Verma <vishal.l.verma@...el.com>, Ira Weiny <ira.weiny@...el.com>,
 Dan Williams <dan.j.williams@...el.com>,
 Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 Yazen Ghannam <yazen.ghannam@....com>, Terry Bowman <terry.bowman@....com>,
 Dave Jiang <dave.jiang@...el.com>, tony.luck@...el.com,
 Gregory Price <gourry@...rry.net>
Subject: Re: "invalid agent type: 1" in acpi/ghes, cper: Recognize and cache
 CXL Protocol errors

On 2025-07-28 09:25, Koralahalli Channabasappa, Smita wrote:

> On 7/22/2025 12:24 PM, Marc Herbert wrote:

>>    The code below triggers the error "invalid agent type: 1" in Intel
>> validation (internal issue 15018133056)
>>
>> It's not clear to anyone we asked why you did not include RCH_DP in
>> the `switch (prot_err->agent_type)` in cxl_cper_post_prot_err() below.
>>
>> I can see how RCH_DP is special in cxl_cper_PRINT_prot_err() and I can
>> even understand (despite my near-zero CPER knowledge) some of the
>> special cases there. But in cxl_cper_post_prot_err() here, it's not
>> clear why RCH_DP would be rejected. Could this be an oversight? If not,
>> a comment with a short explanation would not hurt.
>>
> 
> You're right. RCH_DP was excluded because it doesn’t report a valid
> SBDF in the CPER record. Instead, it provides only the RCRB base
> address.
> 
> I haven't thoroughly investigated whether SBDF can be reliably derived
> from the RCRB base. There might be a platform-specific mechanism for
> that, but at the time, it seemed non-trivial to implement. Introducing
> additional infrastructure solely to support RCH_DP felt like it was
> adding more complexity.
> 
> I agree that a brief comment explaining this rationale would help. I'm
> okay if you plan to include a fixup for this along with the one for
> the device serial number.

If I understood you correctly, I think a different error message
would be much better than a comment. Like this?

--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -730,6 +730,9 @@ static void cxl_cper_post_prot_err(struct cxl_cper_sec_prot_err *prot_err,
 		memcpy(&wd.ras_cap, cap_start, sizeof(wd.ras_cap));
 		wd.severity = cper_severity_to_aer(severity);
 		break;
+	case RCH_DP:
+		pr_err_ratelimited("CXL CPER agent type unsupported: RCH_DP\n");
+		return;
 	default:
 		pr_err_ratelimited("CXL CPER invalid agent type: %d\n",
 				   prot_err->agent_type);