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From:   kys@linuxonhyperv.com
To:     gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com,
        jasowang@redhat.com, sthemmin@microsoft.com,
        Michael.H.Kelley@microsoft.com, vkuznets@redhat.com
Cc:     Dexuan Cui <decui@microsoft.com>,
        "K . Y . Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>, stable@vger.kernel.org
Subject: [PATCH 1/2] Drivers: hv: vmbus: check the creation_status in vmbus_establish_gpadl()
Date:   Mon, 26 Nov 2018 02:29:56 +0000
Message-Id: <20181126022958.11320-1-kys@linuxonhyperv.com>
In-Reply-To: <20181126022821.11269-1-kys@linuxonhyperv.com>
References: <20181126022821.11269-1-kys@linuxonhyperv.com>
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From: Dexuan Cui <decui@microsoft.com>

This is a longstanding issue: if the vmbus upper-layer drivers try to
consume too many GPADLs, the host may return with an error
0xC0000044 (STATUS_QUOTA_EXCEEDED), but currently we forget to check
the creation_status, and hence we can pass an invalid GPADL handle
into the OPEN_CHANNEL message, and get an error code 0xc0000225 in
open_info->response.open_result.status, and finally we hang in
vmbus_open() -> "goto error_free_info" -> vmbus_teardown_gpadl().

With this patch, we can exit gracefully on STATUS_QUOTA_EXCEEDED.

Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index f96a77b18bb9..ce0ba2062723 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -516,6 +516,14 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 	}
 	wait_for_completion(&msginfo->waitevent);
 
+	if (msginfo->response.gpadl_created.creation_status != 0) {
+		pr_err("Failed to establish GPADL: err = 0x%x\n",
+		       msginfo->response.gpadl_created.creation_status);
+
+		ret = -EDQUOT;
+		goto cleanup;
+	}
+
 	if (channel->rescind) {
 		ret = -ENODEV;
 		goto cleanup;
-- 
2.19.1