The patch below does not apply to the 5.10-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-5.10.y git checkout FETCH_HEAD git cherry-pick -x 0913ec336a6c0c4a2b296bd9f74f8e41c4c83c8c # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024071524-yin-woozy-adaf@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

0913ec336a6c ("net: ks8851: Fix deadlock with the SPI chip variant") 317a215d4932 ("net: ks8851: Fix another TX stall caused by wrong ISR flag handling") e0863634bf9f ("net: ks8851: Queue RX packets in IRQ handler instead of disabling BHs") be0384bf599c ("net: ks8851: Handle softirqs at the end of IRQ thread to fix hang") f96f700449b6 ("net: ks8851: Inline ks8851_rx_skb()") 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") 90f77c1c512f ("net: ethernet: Use netif_rx().") 2dc95a4d30ed ("net: Add dm9051 driver") 47aeea0d57e8 ("net: lan966x: Implement the callback SWITCHDEV_ATTR_ID_BRIDGE_MC_DISABLED") 2e49761e4fd1 ("net: lan966x: Add support for multiple bridge flags") e14f72398df4 ("net: lan966x: Extend switchdev bridge flags") 6d2c186afa5d ("net: lan966x: Add vlan support.") cf2f60897e92 ("net: lan966x: Add support to offload the forwarding.") 5ccd66e01cbe ("net: lan966x: add support for interrupts from analyzer") 2f207cbf0dd4 ("net: vertexcom: Add MSE102x SPI support") 12c2d0a5b8e2 ("net: lan966x: add ethtool configuration and statistics") e18aba8941b4 ("net: lan966x: add mactable support") d28d6d2e37d1 ("net: lan966x: add port module support") db8bcaad5393 ("net: lan966x: add the basic lan966x driver") a97c69ba4f30 ("net: ax88796c: ASIX AX88796C SPI Ethernet Adapter Driver")

thanks,

greg k-h

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

From 0913ec336a6c0c4a2b296bd9f74f8e41c4c83c8c Mon Sep 17 00:00:00 2001 From: Ronald Wahl ronald.wahl@raritan.com Date: Sat, 6 Jul 2024 12:13:37 +0200 Subject: [PATCH] net: ks8851: Fix deadlock with the SPI chip variant

When SMP is enabled and spinlocks are actually functional then there is a deadlock with the 'statelock' spinlock between ks8851_start_xmit_spi and ks8851_irq:

watchdog: BUG: soft lockup - CPU#0 stuck for 27s! call trace: queued_spin_lock_slowpath+0x100/0x284 do_raw_spin_lock+0x34/0x44 ks8851_start_xmit_spi+0x30/0xb8 ks8851_start_xmit+0x14/0x20 netdev_start_xmit+0x40/0x6c dev_hard_start_xmit+0x6c/0xbc sch_direct_xmit+0xa4/0x22c __qdisc_run+0x138/0x3fc qdisc_run+0x24/0x3c net_tx_action+0xf8/0x130 handle_softirqs+0x1ac/0x1f0 __do_softirq+0x14/0x20 ____do_softirq+0x10/0x1c call_on_irq_stack+0x3c/0x58 do_softirq_own_stack+0x1c/0x28 __irq_exit_rcu+0x54/0x9c irq_exit_rcu+0x10/0x1c el1_interrupt+0x38/0x50 el1h_64_irq_handler+0x18/0x24 el1h_64_irq+0x64/0x68 __netif_schedule+0x6c/0x80 netif_tx_wake_queue+0x38/0x48 ks8851_irq+0xb8/0x2c8 irq_thread_fn+0x2c/0x74 irq_thread+0x10c/0x1b0 kthread+0xc8/0xd8 ret_from_fork+0x10/0x20

This issue has not been identified earlier because tests were done on a device with SMP disabled and so spinlocks were actually NOPs.

Now use spin_(un)lock_bh for TX queue related locking to avoid execution of softirq work synchronously that would lead to a deadlock.

Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") Cc: "David S. Miller" davem@davemloft.net Cc: Eric Dumazet edumazet@google.com Cc: Jakub Kicinski kuba@kernel.org Cc: Paolo Abeni pabeni@redhat.com Cc: Simon Horman horms@kernel.org Cc: netdev@vger.kernel.org Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Ronald Wahl ronald.wahl@raritan.com Reviewed-by: Simon Horman horms@kernel.org Link: https://patch.msgid.link/20240706101337.854474-1-rwahl@gmx.de Signed-off-by: Paolo Abeni pabeni@redhat.com

diff --git a/drivers/net/ethernet/micrel/ks8851_common.c b/drivers/net/ethernet/micrel/ks8851_common.c index 6453c92f0fa7..13462811eaae 100644 --- a/drivers/net/ethernet/micrel/ks8851_common.c +++ b/drivers/net/ethernet/micrel/ks8851_common.c @@ -352,11 +352,11 @@ static irqreturn_t ks8851_irq(int irq, void *_ks) netif_dbg(ks, intr, ks->netdev, "%s: txspace %d\n", __func__, tx_space);

- spin_lock(&ks->statelock); + spin_lock_bh(&ks->statelock); ks->tx_space = tx_space; if (netif_queue_stopped(ks->netdev)) netif_wake_queue(ks->netdev); - spin_unlock(&ks->statelock); + spin_unlock_bh(&ks->statelock); }

if (status & IRQ_SPIBEI) { @@ -635,14 +635,14 @@ static void ks8851_set_rx_mode(struct net_device *dev)

/* schedule work to do the actual set of the data if needed */

- spin_lock(&ks->statelock); + spin_lock_bh(&ks->statelock);

if (memcmp(&rxctrl, &ks->rxctrl, sizeof(rxctrl)) != 0) { memcpy(&ks->rxctrl, &rxctrl, sizeof(ks->rxctrl)); schedule_work(&ks->rxctrl_work); }

- spin_unlock(&ks->statelock); + spin_unlock_bh(&ks->statelock); }

static int ks8851_set_mac_address(struct net_device *dev, void *addr) diff --git a/drivers/net/ethernet/micrel/ks8851_spi.c b/drivers/net/ethernet/micrel/ks8851_spi.c index 670c1de966db..3062cc0f9199 100644 --- a/drivers/net/ethernet/micrel/ks8851_spi.c +++ b/drivers/net/ethernet/micrel/ks8851_spi.c @@ -340,10 +340,10 @@ static void ks8851_tx_work(struct work_struct *work)

tx_space = ks8851_rdreg16_spi(ks, KS_TXMIR);

- spin_lock(&ks->statelock); + spin_lock_bh(&ks->statelock); ks->queued_len -= dequeued_len; ks->tx_space = tx_space; - spin_unlock(&ks->statelock); + spin_unlock_bh(&ks->statelock);

ks8851_unlock_spi(ks, &flags); }