From: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx> Sent: Monday, July 14, 2025 3:16 PM
>
> The early failure path in __vmbus_establish_gpadl() doesn't deallocate
> msginfo if the buffer fails to decrypt.
>
> Fix the leak by breaking out the cleanup code into a separate function
> and calling it where required.
>
> Fixes: d4dccf353db80 ("Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM")
> Reported-by: Michael Kelly <mkhlinux@xxxxxxxxxxx>
s/Kelly/Kelley/
> Closes: https://lore.kernel.org/linux-hyperv/SN6PR02MB41573796F9787F67E0E97049D472A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
> Signed-off-by: Roman Kisel <romank@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/hv/channel.c | 32 ++++++++++++++++++++++----------
> 1 file changed, 22 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index 051eeba800f2..0eb300b940db 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -409,6 +409,25 @@ static int create_gpadl_header(enum hv_gpadl_type type, void *kbuffer,
> return 0;
> }
>
> +static void vmbus_free_channel_msginfo(struct vmbus_channel_msginfo *msginfo)
> +{
> + unsigned long flags;
> + struct vmbus_channel_msginfo *submsginfo, *tmp;
> +
> + if (!msginfo)
> + return;
> +
> + spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
> + list_del(&msginfo->msglistentry);
> + spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
> + list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
> + msglistentry) {
> + kfree(submsginfo);
> + }
> +
> + kfree(msginfo);
> +}
> +
> /*
> * __vmbus_establish_gpadl - Establish a GPADL for a buffer or ringbuffer
> *
> @@ -428,7 +447,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
> struct vmbus_channel_gpadl_header *gpadlmsg;
> struct vmbus_channel_gpadl_body *gpadl_body;
> struct vmbus_channel_msginfo *msginfo = NULL;
> - struct vmbus_channel_msginfo *submsginfo, *tmp;
> + struct vmbus_channel_msginfo *submsginfo;
> struct list_head *curr;
> u32 next_gpadl_handle;
> unsigned long flags;
> @@ -458,6 +477,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
> dev_warn(&channel->device_obj->device,
> "Failed to set host visibility for new GPADL %d.\n",
> ret);
> + vmbus_free_channel_msginfo(msginfo);
I don't think this works. At this point, msginfo has not been added to the global
vmbus_connection.chn_msg_list. vmbus_free_channel_msginfo() will try to
remove it from that list using list_del(), and will fault on a NULL pointer.
> return ret;
> }
> }
> @@ -531,15 +551,7 @@ static int __vmbus_establish_gpadl(struct vmbus_channel *channel,
>
>
> cleanup:
> - spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
> - list_del(&msginfo->msglistentry);
> - spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
> - list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
> - msglistentry) {
> - kfree(submsginfo);
> - }
> -
> - kfree(msginfo);
> + vmbus_free_channel_msginfo(msginfo);
>
> if (ret) {
> /*
> --
> 2.43.0
