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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
        Antoine Tenart <atenart@kernel.org>,
        Tsahee Zidenberg <tsahee@annapurnalabs.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 418/717] irqchip/alpine-msi: Fix freeing of interrupts on allocation error path
Date:   Mon, 28 Dec 2020 13:46:56 +0100
Message-Id: <20201228125040.986771833@linuxfoundation.org>
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From: Marc Zyngier <maz@kernel.org>

[ Upstream commit 3841245e8498a789c65dedd7ffa8fb2fee2c0684 ]

The alpine-msi driver has an interesting allocation error handling,
where it frees the same interrupts repeatedly. Hilarity follows.

This code is probably never executed, but let's fix it nonetheless.

Fixes: e6b78f2c3e14 ("irqchip: Add the Alpine MSIX interrupt controller")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Cc: Tsahee Zidenberg <tsahee@annapurnalabs.com>
Cc: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20201129135525.396671-1-maz@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/irqchip/irq-alpine-msi.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-alpine-msi.c b/drivers/irqchip/irq-alpine-msi.c
index 23a3b877f7f1d..ede02dc2bcd0b 100644
--- a/drivers/irqchip/irq-alpine-msi.c
+++ b/drivers/irqchip/irq-alpine-msi.c
@@ -165,8 +165,7 @@ static int alpine_msix_middle_domain_alloc(struct irq_domain *domain,
 	return 0;
 
 err_sgi:
-	while (--i >= 0)
-		irq_domain_free_irqs_parent(domain, virq, i);
+	irq_domain_free_irqs_parent(domain, virq, i - 1);
 	alpine_msix_free_sgi(priv, sgi, nr_irqs);
 	return err;
 }
-- 
2.27.0