linux-kernel - [PATCH] net: stmmac: Don't call

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Message-Id: <20201008162749.860521-1-john@metanate.com>
Date:   Thu,  8 Oct 2020 17:27:49 +0100
From:   John Keeping <john@...anate.com>
To:     netdev@...r.kernel.org
Cc:     John Keeping <john@...anate.com>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        Jose Abreu <joabreu@...opsys.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] net: stmmac: Don't call _irqoff() with hardirqs enabled

With threadirqs, stmmac_interrupt() is called on a thread with hardirqs
enabled so we cannot call __napi_schedule_irqoff().  Under lockdep it
leads to:

	------------[ cut here ]------------
	WARNING: CPU: 0 PID: 285 at kernel/softirq.c:598 __raise_softirq_irqoff+0x6c/0x1c8
	IRQs not disabled as expected
	Modules linked in: brcmfmac hci_uart btbcm cfg80211 brcmutil
	CPU: 0 PID: 285 Comm: irq/41-eth0 Not tainted 5.4.69-rt39 #1
	Hardware name: Rockchip (Device Tree)
	[<c0110d3c>] (unwind_backtrace) from [<c010c284>] (show_stack+0x10/0x14)
	[<c010c284>] (show_stack) from [<c0855504>] (dump_stack+0xa8/0xe0)
	[<c0855504>] (dump_stack) from [<c0120a9c>] (__warn+0xe0/0xfc)
	[<c0120a9c>] (__warn) from [<c0120e80>] (warn_slowpath_fmt+0x7c/0xa4)
	[<c0120e80>] (warn_slowpath_fmt) from [<c01278c8>] (__raise_softirq_irqoff+0x6c/0x1c8)
	[<c01278c8>] (__raise_softirq_irqoff) from [<c056bccc>] (stmmac_interrupt+0x388/0x4e0)
	[<c056bccc>] (stmmac_interrupt) from [<c0178714>] (irq_forced_thread_fn+0x28/0x64)
	[<c0178714>] (irq_forced_thread_fn) from [<c0178924>] (irq_thread+0x124/0x260)
	[<c0178924>] (irq_thread) from [<c0142ee8>] (kthread+0x154/0x164)
	[<c0142ee8>] (kthread) from [<c01010bc>] (ret_from_fork+0x14/0x38)
	Exception stack(0xeb7b5fb0 to 0xeb7b5ff8)
	5fa0:                                     00000000 00000000 00000000 00000000
	5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
	5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
	irq event stamp: 48
	hardirqs last  enabled at (50): [<c085c200>] prb_unlock+0x7c/0x8c
	hardirqs last disabled at (51): [<c085c0dc>] prb_lock+0x58/0x100
	softirqs last  enabled at (0): [<c011e770>] copy_process+0x550/0x1654
	softirqs last disabled at (25): [<c01786ec>] irq_forced_thread_fn+0x0/0x64
	---[ end trace 0000000000000002 ]---

Use __napi_schedule() instead which will save & restore the interrupt
state.

Fixes: 4ccb45857c2c ("net: stmmac: Fix NAPI poll in TX path when in multi-queue")
Signed-off-by: John Keeping <john@...anate.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 220626a8d499..c331b829f60a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2145,7 +2145,7 @@ static int stmmac_napi_check(struct stmmac_priv *priv, u32 chan)
 			spin_lock_irqsave(&ch->lock, flags);
 			stmmac_disable_dma_irq(priv, priv->ioaddr, chan, 1, 0);
 			spin_unlock_irqrestore(&ch->lock, flags);
-			__napi_schedule_irqoff(&ch->rx_napi);
+			__napi_schedule(&ch->rx_napi);
 		}
 	}
 
@@ -2154,7 +2154,7 @@ static int stmmac_napi_check(struct stmmac_priv *priv, u32 chan)
 			spin_lock_irqsave(&ch->lock, flags);
 			stmmac_disable_dma_irq(priv, priv->ioaddr, chan, 0, 1);
 			spin_unlock_irqrestore(&ch->lock, flags);
-			__napi_schedule_irqoff(&ch->tx_napi);
+			__napi_schedule(&ch->tx_napi);
 		}
 	}
 
-- 
2.28.0