linux-kernel - [PATCH v4 2/2] Drivers: hv: vmbus: Log on missing offers if any

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20241118070725.3221-3-namjain@linux.microsoft.com>
Date: Sun, 17 Nov 2024 23:07:25 -0800
From: Naman Jain <namjain@...ux.microsoft.com>
To: "K . Y . Srinivasan" <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>,
	Dexuan Cui <decui@...rosoft.com>
Cc: linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Naman Jain <namjain@...ux.microsoft.com>,
	John Starks <jostarks@...rosoft.com>,
	jacob.pan@...ux.microsoft.com,
	Easwar Hariharan <eahariha@...ux.microsoft.com>,
	Michael Kelley <mhklinux@...look.com>,
	Saurabh Singh Sengar <ssengar@...ux.microsoft.com>
Subject: [PATCH v4 2/2] Drivers: hv: vmbus: Log on missing offers if any

From: John Starks <jostarks@...rosoft.com>

When resuming from hibernation, log any channels that were present
before hibernation but now are gone.
In general, the boot-time devices configured for a resuming VM should be
the same as the devices in the VM at the time of hibernation. It's
uncommon for the configuration to have been changed such that offers
are missing. Changing the configuration violates the rules for
hibernation anyway.
The cleanup of missing channels is not straight-forward and dependent
on individual device driver functionality and implementation,
so it can be added in future with separate changes.

Signed-off-by: John Starks <jostarks@...rosoft.com>
Co-developed-by: Naman Jain <namjain@...ux.microsoft.com>
Signed-off-by: Naman Jain <namjain@...ux.microsoft.com>
Reviewed-by: Easwar Hariharan <eahariha@...ux.microsoft.com>
Reviewed-by: Saurabh Sengar <ssengar@...ux.microsoft.com>
---
Changes since v3:
Fixed minor checkpatch style warning coming with "--strict" option,
addressing Saurabh's comments.

Changes since v2:
* Addressed Michael's comments:
  * Changed commit msg as per suggestions
* Addressed Dexuan's comments, which came up in offline discussion:
  * Minor additions in commit subject.

Changes since v1:
* Added Easwar's Reviewed-By tag
* Addressed Saurabh's comments:
  * Added a note for missing channel cleanup in comments and commit msg
---
 drivers/hv/vmbus_drv.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index bd3fc41dc06b..6b27d3abc2db 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2462,6 +2462,7 @@ static int vmbus_bus_suspend(struct device *dev)
 
 static int vmbus_bus_resume(struct device *dev)
 {
+	struct vmbus_channel *channel;
 	struct vmbus_channel_msginfo *msginfo;
 	size_t msgsize;
 	int ret;
@@ -2494,6 +2495,22 @@ static int vmbus_bus_resume(struct device *dev)
 
 	vmbus_request_offers();
 
+	mutex_lock(&vmbus_connection.channel_mutex);
+	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
+		if (channel->offermsg.child_relid != INVALID_RELID)
+			continue;
+
+		/* hvsock channels are not expected to be present. */
+		if (is_hvsock_channel(channel))
+			continue;
+
+		pr_err("channel %pUl/%pUl not present after resume.\n",
+		       &channel->offermsg.offer.if_type,
+		       &channel->offermsg.offer.if_instance);
+		/* ToDo: Cleanup these channels here */
+	}
+	mutex_unlock(&vmbus_connection.channel_mutex);
+
 	/* Reset the event for the next suspend. */
 	reinit_completion(&vmbus_connection.ready_for_suspend_event);
 
-- 
2.34.1