From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Philipp David <pd-lkml@3b.pm>,
	Aleksandr Loktionov <aleksandr.loktionov@intel.com>,
	Dima Ruinskiy <dima.ruinskiy@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.12 011/220] igc: fix netdev not re-attached after resume if interface is down
Date: Thu, 20 Aug 2026 16:53:21 +0200
Message-ID: <20260820145223.831267044@linuxfoundation.org>
In-Reply-To: <20260820145223.480031205@linuxfoundation.org>
References: <20260820145223.480031205@linuxfoundation.org>
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6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Philipp David <pd-lkml@3b.pm>

[ Upstream commit b0ce5fd9fabe7c79463cf4602217d4dfeff5b1fd ]

__igc_resume() calls netif_device_attach() only inside the
netif_running() branch, so an interface that was down during suspend
is never re-attached on resume. It then stays in the not-present state
that __igc_shutdown() set via netif_device_detach(): ethtool reports
ENODEV and every attempt to bring the interface up fails the
netif_device_present() check in __dev_open() with -ENODEV, silently,
since __igc_resume() returns 0. Only reloading the driver recovers the
device.

This is easy to hit in practice because NetworkManager brings managed
interfaces down before sleep unless Wake-on-LAN is configured, making
the adapter unusable after every suspend/resume cycle with WoL
disabled.

Re-attach the netdev on every successful resume, as igb and e1000e do.

Fixes: 6f31d6b643a3 ("igc: Refactor runtime power management flow")
Cc: stable@vger.kernel.org
Signed-off-by: Philipp David <pd-lkml@3b.pm>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Reviewed-by: Dima Ruinskiy <dima.ruinskiy@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://patch.msgid.link/20260804222205.1580328-11-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/igc/igc_main.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 6fcf4fd7ee19..ecc33f797e37 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -7405,11 +7405,13 @@ static int igc_resume(struct device *dev)
 
 	if (netif_running(netdev)) {
 		err = __igc_open(netdev, true);
-		if (!err)
-			netif_device_attach(netdev);
+		if (err)
+			return err;
 	}
 
-	return err;
+	netif_device_attach(netdev);
+
+	return 0;
 }
 
 static int igc_runtime_resume(struct device *dev)
-- 
2.53.0