Commit 37df9f3f authored by Lv Yunlong's avatar Lv Yunlong Committed by Wei Liu
Browse files

video: hyperv_fb: Fix a double free in hvfb_probe 



Function hvfb_probe() calls hvfb_getmem(), expecting upon return that
info->apertures is either NULL or points to memory that should be freed
by framebuffer_release().  But hvfb_getmem() is freeing the memory and
leaving the pointer non-NULL, resulting in a double free if an error
occurs or later if hvfb_remove() is called.

Fix this by removing all kfree(info->apertures) calls in hvfb_getmem().
This will allow framebuffer_release() to free the memory, which follows
the pattern of other fbdev drivers.

Fixes: 3a6fb6c4 ("video: hyperv: hyperv_fb: Use physical memory for fb on HyperV Gen 1 VMs.")
Signed-off-by: default avatarLv Yunlong <lyl2019@mail.ustc.edu.cn>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210324103724.4189-1-lyl2019@mail.ustc.edu.cn


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent fe07bfda

drivers/video/fbdev/hyperv_fb.c

+0 −3
Original line number Diff line number Diff line
@@ -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;

}