From: Lv Yunlong <redacted> Sent: Tuesday, March 23, 2021 12:34 AM
quoted hunk ↗ jump to hunk
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).
My patch sets info->apertures to NULL after it was freed to avoid
double free.
Signed-off-by: Lv Yunlong <redacted>
---
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
While I think this works, a slightly better solution might be to remove
all calls to kfree(info->apertures) in hvfb_getmem(), and just let
framebuffer_release() handle freeing the memory. That's what is
done in other drivers that follow the fbdev pattern, and it's less
code overall.
Michael