On 10/16/26 04:35, Yuho Choi wrote:
> virtio_mem_init_kdump() marks the device DRIVER_OK before it checks for
> CONFIG_PROC_VMCORE. Without vmcore support it then fails with -EBUSY,
> and virtio_mem_probe() deletes the virtqueue on that error path without
> resetting the device first, so the device is left believing the driver
> is ready while its queue points at memory that has been freed.
>
> Before commit a9403425b3cf ("virtio-mem: mark device ready before
> registering callbacks in kdump mode"), virtio_mem_probe() called
> virtio_device_ready() only after virtio_mem_init() had succeeded, so this
> path never exposed a ready device.
>
> Move virtio_device_ready() into the CONFIG_PROC_VMCORE branch, right
> before the vmcore callbacks that need it are registered, so the -EBUSY
> path never sets DRIVER_OK.
>
> Fixes: a9403425b3cf ("virtio-mem: mark device ready before registering
> callbacks in kdump mode")
> Cc: [email protected]
Which kdump kernel exists that does not enable CONFIG_PROC_VMCORE?
IOW, why should this be stable material?
> Signed-off-by: Yuho Choi <[email protected]>
> ---
> drivers/virtio/virtio_mem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
> index e18dd736f2ec..b28d2da7d5b6 100644
> --- a/drivers/virtio/virtio_mem.c
> +++ b/drivers/virtio/virtio_mem.c
> @@ -2817,9 +2817,9 @@ static int virtio_mem_vmcore_get_device_ram(struct
> vmcore_cb *cb,
>
> static int virtio_mem_init_kdump(struct virtio_mem *vm)
> {
> +#ifdef CONFIG_PROC_VMCORE
> /* We must be prepared to receive a callback immediately. */
> virtio_device_ready(vm->vdev);
> -#ifdef CONFIG_PROC_VMCORE
> dev_info(&vm->vdev->dev, "memory hot(un)plug disabled in kdump
> kernel\n");
> vm->vmcore_cb.pfn_is_ram = virtio_mem_vmcore_pfn_is_ram;
> #ifdef CONFIG_PROC_VMCORE_DEVICE_RAM
LGTM, but I am pretty sure it does not make any difference in practice?
--
Cheers,
David
