linux-kernel - [PATCH AUTOSEL 5.4 107/134] Drivers: hv: vmbus: Fix crash handler reset of Hyper-V synic

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Message-Id: <20191211151150.19073-107-sashal@kernel.org>
Date:   Wed, 11 Dec 2019 10:11:23 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Michael Kelley <mikelley@...rosoft.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Dexuan Cui <decui@...rosoft.com>,
        Sasha Levin <sashal@...nel.org>, devel@...uxdriverproject.org
Subject: [PATCH AUTOSEL 5.4 107/134] Drivers: hv: vmbus: Fix crash handler reset of Hyper-V synic

From: Michael Kelley <mikelley@...rosoft.com>

[ Upstream commit 7a1323b5dfe44a9013a2cc56ef2973034a00bf88 ]

The crash handler calls hv_synic_cleanup() to shutdown the
Hyper-V synthetic interrupt controller.  But if the CPU
that calls hv_synic_cleanup() has a VMbus channel interrupt
assigned to it (which is likely the case in smaller VM sizes),
hv_synic_cleanup() returns an error and the synthetic
interrupt controller isn't shutdown.  While the lack of
being shutdown hasn't caused a known problem, it still
should be fixed for highest reliability.

So directly call hv_synic_disable_regs() instead of
hv_synic_cleanup(), which ensures that the synic is always
shutdown.

Signed-off-by: Michael Kelley <mikelley@...rosoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Reviewed-by: Dexuan Cui <decui@...rosoft.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/hv/vmbus_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 53a60c81e220d..05ead1735c6e3 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2308,7 +2308,7 @@ static void hv_crash_handler(struct pt_regs *regs)
 	vmbus_connection.conn_state = DISCONNECTED;
 	cpu = smp_processor_id();
 	hv_stimer_cleanup(cpu);
-	hv_synic_cleanup(cpu);
+	hv_synic_disable_regs(cpu);
 	hyperv_cleanup();
 };
 
-- 
2.20.1