netdev - [PATCH] e1000e: Link flap workaround option for false IRP events

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-next>] [day] [month] [year] [list]

Message-ID: <20250226194422.1030419-1-mpearson-lenovo@squebb.ca>
Date: Wed, 26 Feb 2025 14:44:12 -0500
From: Mark Pearson <mpearson-lenovo@...ebb.ca>
To: mpearson-lenovo@...ebb.ca
Cc: anthony.l.nguyen@...el.com,
	przemyslaw.kitszel@...el.com,
	andrew+netdev@...n.ch,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	intel-wired-lan@...ts.osuosl.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] e1000e: Link flap workaround option for false IRP events

Issue is seen on some Lenovo desktop workstations where there
is a false IRP event which triggers a link flap.
Condition is rare and only seen on networks where link speed
may differ along the path between nodes (e.g 10M/100M)

Intel are not able to determine root cause but provided a
workaround that does fix the issue. Tested extensively at Lenovo.

Adding a module option to enable this workaround for users
who are impacted by this issue.

Signed-off-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 286155efcedf..06774fb4b2dd 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -37,6 +37,10 @@ static int debug = -1;
 module_param(debug, int, 0);
 MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");
 
+static int false_irp_workaround;
+module_param(false_irp_workaround, int, 0);
+MODULE_PARM_DESC(false_irp_workaround, "Enable workaround for rare false IRP event causing link flap");
+
 static const struct e1000_info *e1000_info_tbl[] = {
 	[board_82571]		= &e1000_82571_info,
 	[board_82572]		= &e1000_82572_info,
@@ -1757,6 +1761,21 @@ static irqreturn_t e1000_intr_msi(int __always_unused irq, void *data)
 	/* read ICR disables interrupts using IAM */
 	if (icr & E1000_ICR_LSC) {
 		hw->mac.get_link_status = true;
+
+		/*
+		 * False IRP workaround
+		 * Issue seen on Lenovo P5 and P7 workstations where if there
+		 * are different link speeds in the network a false IRP event
+		 * is received, leading to a link flap.
+		 * Intel unable to determine root cause. This read prevents
+		 * the issue occurring
+		 */
+		if (false_irp_workaround) {
+			u16 phy_data;
+
+			e1e_rphy(hw, PHY_REG(772, 26), &phy_data);
+		}
+
 		/* ICH8 workaround-- Call gig speed drop workaround on cable
 		 * disconnect (LSC) before accessing any PHY registers
 		 */
-- 
2.43.0