From 5f29dd540fe5ea3c826fc8ec759ba488b31f9707 Mon Sep 17 00:00:00 2001 From: Fan Wu Date: Mon, 9 Mar 2026 13:24:09 +0000 Subject: [PATCH] net: ethernet: arc: emac: quiesce interrupts before requesting IRQ commit 2503d08f8a2de618e5c3a8183b250ff4a2e2d52c upstream. Normal RX/TX interrupts are enabled later, in arc_emac_open(), so probe should not see interrupt delivery in the usual case. However, hardware may still present stale or latched interrupt status left by firmware or the bootloader. If probe later unwinds after devm_request_irq() has installed the handler, such a stale interrupt can still reach arc_emac_intr() during teardown and race with release of the associated net_device. Avoid that window by putting the device into a known quiescent state before requesting the IRQ: disable all EMAC interrupt sources and clear any pending EMAC interrupt status bits. This keeps the change hardware-focused and minimal, while preventing spurious IRQ delivery from leftover state. Fixes: e4f2379db6c6 ("ethernet/arc/arc_emac - Add new driver") Cc: stable@vger.kernel.org Signed-off-by: Fan Wu Link: https://patch.msgid.link/20260309132409.584966-1-fanwu01@zju.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/arc/emac_main.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/net/ethernet/arc/emac_main.c b/drivers/net/ethernet/arc/emac_main.c index bafa63e5ce25..131413379c1c 100644 --- a/drivers/net/ethernet/arc/emac_main.c +++ b/drivers/net/ethernet/arc/emac_main.c @@ -934,6 +934,17 @@ int arc_emac_probe(struct net_device *ndev, int interface) /* Set poll rate so that it polls every 1 ms */ arc_reg_set(priv, R_POLLRATE, clock_frequency / 1000000); + /* + * Put the device into a known quiescent state before requesting + * the IRQ. Clear only EMAC interrupt status bits here; leave the + * MDIO completion bit alone and avoid writing TXPL_MASK, which is + * used to force TX polling rather than acknowledge interrupts. + */ + arc_reg_set(priv, R_ENABLE, 0); + arc_reg_set(priv, R_STATUS, RXINT_MASK | TXINT_MASK | ERR_MASK | + TXCH_MASK | MSER_MASK | RXCR_MASK | + RXFR_MASK | RXFL_MASK); + ndev->irq = irq; dev_info(dev, "IRQ is %d\n", ndev->irq);