[PATCH v2] video: hyperv_fb: Fix a double free in hvfb_probe

From: Lv Yunlong
Date: Wed Mar 24 2021 - 06:38:27 EST


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 for the
second time in framebuffer_release(info).

My patch removes all kfree(info->apertures) instead of set info->apertures
to NULL. It is because that let framebuffer_release() handle freeing the
memory flows the fbdev pattern, and less code overall.

Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
---
drivers/video/fbdev/hyperv_fb.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index c8b0ae676809..4dc9077dd2ac 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -1031,7 +1031,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
if (!pdev) {
pr_err("Unable to find PCI Hyper-V video\n");
- kfree(info->apertures);
return -ENODEV;
}

@@ -1129,7 +1128,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
} else {
pci_dev_put(pdev);
}
- kfree(info->apertures);

return 0;

@@ -1141,7 +1139,6 @@ static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
err1:
if (!gen2vm)
pci_dev_put(pdev);
- kfree(info->apertures);

return -ENOMEM;
}
--
2.25.1