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Message-Id: <20230208113424.864881-1-mgamal@redhat.com>
Date: Wed, 8 Feb 2023 13:34:24 +0200
From: Mohammed Gamal <mgamal@...hat.com>
To: linux-hyperv@...r.kernel.org, mikelley@...rosoft.com,
parri.andrea@...il.com, wei.liu@...nel.org
Cc: linux-kernel@...r.kernel.org, decui@...rosoft.com,
haiyangz@...rosoft.com, vkuznets@...hat.com,
Mohammed Gamal <mgamal@...hat.com>
Subject: [PATCH] Drivers: vmbus: Check for channel allocation before looking up relids
relid2channel() assumes vmbus channel array to be allocated when called.
However, if the guest receives a vmbus interrupt during driver initialization
before vmbus_connect() is called or if vmbus_connect() fails, the vmbus
interrupt service routine is called which in turn calls relid2channel()
and can cause a null pointer dereference.
So Make relid2channel() check if vmbus channels is allocated first and return
NULL to the caller if not allocated.
Fixes: 8b6a877c060e ("Drivers: hv: vmbus: Replace the per-CPU channel lists with a global array of channels")
Signed-off-by: Mohammed Gamal <mgamal@...hat.com>
---
drivers/hv/connection.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 9dc27e5d367a..5c603c4f75a2 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -409,6 +409,8 @@ void vmbus_disconnect(void)
*/
struct vmbus_channel *relid2channel(u32 relid)
{
+ if (WARN_ON(vmbus_connection.channels == NULL))
+ return NULL;
if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
return NULL;
return READ_ONCE(vmbus_connection.channels[relid]);
--
2.38.1
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