Subject: FAILED: patch "[PATCH] cxl/ras: Fix cxl_rch_get_aer_severity() wrong severity" failed to apply to 6.12-stable tree
To: terry.bowman@amd.com,alison.schofield@intel.com,dave.jiang@intel.com,icheng@nvidia.com,jonathan.cameron@oss.qualcomm.com
Cc: <stable@vger.kernel.org>
From: <gregkh@linuxfoundation.org>
Date: Thu, 03 Sep 2026 15:54:17 +0200
Message-ID: <2026090317-roundish-company-df16@gregkh>
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The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 9d399526128bae184b153deab42b49f5f3eea2ed
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090317-roundish-company-df16@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:


thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9d399526128bae184b153deab42b49f5f3eea2ed Mon Sep 17 00:00:00 2001
From: Terry Bowman <terry.bowman@amd.com>
Date: Mon, 3 Aug 2026 17:17:58 -0500
Subject: [PATCH] cxl/ras: Fix cxl_rch_get_aer_severity() wrong severity
 register

cxl_rch_get_aer_severity() classifies RCH Downstream Port uncorrectable
errors as fatal or non-fatal by ANDing uncorrectable status with
PCI_ERR_ROOT_FATAL_RCV. This is wrong because PCI_ERR_ROOT_FATAL_RCV is a
Root Error Status register bit (bit 6), not a severity bit. ANDing it
against uncorrectable status tests a reserved bit and produces incorrect
severity classification.

Fix by ANDing the unmasked uncor_status against uncor_severity. Per
PCIe Base Spec r6.0 Section 7.8.4.4, each bit in the Uncorrectable
Error Severity register indicates whether the corresponding error is
fatal (1) or non-fatal (0).

Fixes: 6ac07883dbb5 ("cxl/pci: Add RCH downstream port error logging")
Cc: stable@vger.kernel.org
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Richard Cheng <icheng@nvidia.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/20260803221810.3685703-3-terry.bowman@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

diff --git a/drivers/cxl/core/ras_rch.c b/drivers/cxl/core/ras_rch.c
index 8a3965edaa12..e0e01aa5eba6 100644
--- a/drivers/cxl/core/ras_rch.c
+++ b/drivers/cxl/core/ras_rch.c
@@ -94,11 +94,11 @@ static bool cxl_rch_get_aer_info(void __iomem *aer_base,
 static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
 				     int *severity)
 {
-	if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
-		if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
-			*severity = AER_FATAL;
-		else
-			*severity = AER_NONFATAL;
+	u32 uncor_status = aer_regs->uncor_status & ~aer_regs->uncor_mask;
+
+	if (uncor_status) {
+		*severity = (uncor_status & aer_regs->uncor_severity) ?
+			     AER_FATAL : AER_NONFATAL;
 		return true;
 	}