linux-kernel - [PATCH 4.14 124/159] net: dsa: mv88e6xxx: Fix interrupt masking on removal

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Date:   Fri, 23 Feb 2018 19:27:12 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...oirfairelinux.com>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <alexander.levin@...izon.com>
Subject: [PATCH 4.14 124/159] net: dsa: mv88e6xxx: Fix interrupt masking on removal

4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Andrew Lunn <andrew@...n.ch>


[ Upstream commit 3d5fdba1842bdd2eef29364c660558cb4cbb3fe0 ]

When removing the interrupt handling code, we should mask the
generation of interrupts. The code however unmasked all
interrupts. This can then cause a new interrupt. We then get into a
deadlock where the interrupt thread is waiting to run, and the code
continues, trying to remove the interrupt handler, which means waiting
for the thread to complete. On a UP machine this deadlocks.

Fix so we really mask interrupts in the hardware. The same error is
made in the error path when install the interrupt handling code.

Fixes: 3460a5770ce9 ("net: dsa: mv88e6xxx: Mask g1 interrupts and free interrupt")
Signed-off-by: Andrew Lunn <andrew@...n.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/dsa/mv88e6xxx/chip.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -339,7 +339,7 @@ static void mv88e6xxx_g1_irq_free(struct
 	u16 mask;
 
 	mv88e6xxx_g1_read(chip, MV88E6XXX_G1_CTL1, &mask);
-	mask |= GENMASK(chip->g1_irq.nirqs, 0);
+	mask &= ~GENMASK(chip->g1_irq.nirqs, 0);
 	mv88e6xxx_g1_write(chip, MV88E6XXX_G1_CTL1, mask);
 
 	free_irq(chip->irq, chip);
@@ -395,7 +395,7 @@ static int mv88e6xxx_g1_irq_setup(struct
 	return 0;
 
 out_disable:
-	mask |= GENMASK(chip->g1_irq.nirqs, 0);
+	mask &= ~GENMASK(chip->g1_irq.nirqs, 0);
 	mv88e6xxx_g1_write(chip, MV88E6XXX_G1_CTL1, mask);
 
 out_mapping: