From 80b4034890f222058afc749fc11b66fc8a53b6b4 Mon Sep 17 00:00:00 2001 From: Saurabh Sengar Date: Thu, 29 Aug 2024 12:43:11 +0530 Subject: [PATCH] uio_hv_generic: Fix kernel NULL pointer dereference in hv_uio_rescind commit fb1adbd7e50f3d2de56d0a2bb0700e2e819a329e upstream. For primary VM Bus channels, primary_channel pointer is always NULL. This pointer is valid only for the secondary channels. Also, rescind callback is meant for primary channels only. Fix NULL pointer dereference by retrieving the device_obj from the parent for the primary channel. Cc: stable@vger.kernel.org Fixes: ca3cda6fcf1e ("uio_hv_generic: add rescind support") Signed-off-by: Saurabh Sengar Signed-off-by: Naman Jain Link: https://lore.kernel.org/r/20240829071312.1595-2-namjain@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman --- drivers/uio/uio_hv_generic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c index c31febe90..a09e062b8 100755 --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -104,10 +104,11 @@ static void hv_uio_channel_cb(void *context) /* * Callback from vmbus_event when channel is rescinded. + * It is meant for rescind of primary channels only. */ static void hv_uio_rescind(struct vmbus_channel *channel) { - struct hv_device *hv_dev = channel->primary_channel->device_obj; + struct hv_device *hv_dev = channel->device_obj; struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev); /*