netdev - [PATCH net v2] ionic: Prevent tx_timeout due to frequent doorbell ringing

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: <20240822192557.9089-1-brett.creeley@amd.com>
Date: Thu, 22 Aug 2024 12:25:57 -0700
From: Brett Creeley <brett.creeley@....com>
To: <netdev@...r.kernel.org>, <davem@...emloft.net>, <kuba@...nel.org>,
	<edumazet@...gle.com>, <pabeni@...hat.com>
CC: <shannon.nelson@....com>, <brett.creeley@....com>,
	<stable@...r.kernel.org>
Subject: [PATCH net v2] ionic: Prevent tx_timeout due to frequent doorbell ringing

With recent work to the doorbell workaround code a small hole was
introduced that could cause a tx_timeout. This happens if the rx
dbell_deadline goes beyond the netdev watchdog timeout set by the driver
(i.e. 2 seconds). Fix this by changing the netdev watchdog timeout to 5
seconds and reduce the max rx dbell_deadline to 4 seconds.

The test that can reproduce the issue being fixed is a multi-queue send
test via pktgen with the "burst" setting to 1. This causes the queue's
doorbell to be rung on every packet sent to the driver, which may result
in the device missing doorbells due to the high doorbell rate.

Cc: stable@...r.kernel.org
Fixes: 4ded136c78f8 ("ionic: add work item for missed-doorbell check")
Signed-off-by: Brett Creeley <brett.creeley@....com>
Reviewed-by: Shannon Nelson <shannon.nelson@....com>
---
v2:
 - Drop budget == 0 patch to expedite getting this patch merged due to
   the budget == 0 patch being more complicated than we originally
   thought.

v1:
 - https://lore.kernel.org/netdev/20240813234122.53083-1-brett.creeley@amd.com/

 drivers/net/ethernet/pensando/ionic/ionic_dev.h | 2 +-
 drivers/net/ethernet/pensando/ionic/ionic_lif.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_dev.h b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
index c647033f3ad2..f2f07bf88545 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_dev.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.h
@@ -32,7 +32,7 @@
 #define IONIC_ADMIN_DOORBELL_DEADLINE	(HZ / 2)	/* 500ms */
 #define IONIC_TX_DOORBELL_DEADLINE	(HZ / 100)	/* 10ms */
 #define IONIC_RX_MIN_DOORBELL_DEADLINE	(HZ / 100)	/* 10ms */
-#define IONIC_RX_MAX_DOORBELL_DEADLINE	(HZ * 5)	/* 5s */
+#define IONIC_RX_MAX_DOORBELL_DEADLINE	(HZ * 4)	/* 4s */
 
 struct ionic_dev_bar {
 	void __iomem *vaddr;
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index aa0cc31dfe6e..86774d9922d8 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -3220,7 +3220,7 @@ int ionic_lif_alloc(struct ionic *ionic)
 	netdev->netdev_ops = &ionic_netdev_ops;
 	ionic_ethtool_set_ops(netdev);
 
-	netdev->watchdog_timeo = 2 * HZ;
+	netdev->watchdog_timeo = 5 * HZ;
 	netif_carrier_off(netdev);
 
 	lif->identity = lid;
-- 
2.17.1