Thanks for your patch.
I would like to change the prefix to "video: hyperv_fb:" to be more
specific.
On Tue, Mar 23, 2021 at 12:33:50AM -0700, Lv Yunlong wrote:
> In function hvfb_probe in hyperv_fb.c, it calls hvfb_getmem(hdev, info)
> and return err when info->apertures is freed.
>
> In the error1 label of hvfb_probe, info->apertures will be freed twice
> by framebuffer_release(info).
>
I would say "freed for the second time" here. What you wrote reads to me
fraembuffer_release frees the buffer twice all by itself.
> My patch sets info->apertures to NULL after it was freed to avoid
> double free.
>
I think this approach works. I would like to give other people a chance
to comment though.
Fixes: 3a6fb6c4255c ("video: hyperv: hyperv_fb: Use physical memory for fb on HyperV Gen 1 VMs.")
> Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
> ---
> drivers/video/fbdev/hyperv_fb.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> index c8b0ae676809..2fc9b507e73a 100644
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ b/drivers/video/fbdev/hyperv_fb.c
> @@ -1032,6 +1032,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
> if (!pdev) {
> pr_err("Unable to find PCI Hyper-V video\n");
> kfree(info->apertures);
> + info->apertures = NULL;
> return -ENODEV;
> }
>
> @@ -1130,6 +1131,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
> pci_dev_put(pdev);
> }
> kfree(info->apertures);
> + info->apertures = NULL;
>
> return 0;
>
> @@ -1142,6 +1144,7 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
> if (!gen2vm)
> pci_dev_put(pdev);
> kfree(info->apertures);
> + info->apertures = NULL;
>
> return -ENOMEM;
> }
> --
> 2.25.1
>
>
