Hi
Am 16.09.26 um 23:06 schrieb Deucher, Alexander:
Public
-----Original Message-----
From: Wentao Liang <[email protected]>
Sent: Wednesday, September 16, 2026 3:38 AM
To: Deucher, Alexander <[email protected]>
Cc: [email protected]; [email protected]; linux-
[email protected]; [email protected]; Wentao Liang
<[email protected]>; [email protected]
Subject: [PATCH] firmware/sysfb: Fix device reference count leak in
sysfb_disable()
In sysfb_disable(), parent is obtained via sysfb_parent_dev(si), which calls
screen_info_pci_dev(si) and returns a pointer to &pdev->dev with an acquired
reference count. However, sysfb_disable() does not release this reference
before returning, leading to a device reference leak.
Fix this by checking if parent is not an ERR_PTR and calling
put_device(parent) before releasing the mutex.
Fixes: b49420d6a1ae ("video/aperture: optionally match the device in
sysfb_disable()")
Cc: [email protected]
Signed-off-by: Wentao Liang <[email protected]>
---
drivers/firmware/sysfb.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c index
8833582c1883..11c5ce128a6c 100644
--- a/drivers/firmware/sysfb.c
+++ b/drivers/firmware/sysfb.c
@@ -71,9 +71,12 @@ void sysfb_disable(struct device *dev)
mutex_lock(&disable_lock);
parent = sysfb_parent_dev(si);
- if (!dev || !parent || dev == parent) {
- sysfb_unregister();
- disabled = true;
+ if (!IS_ERR(parent)) {
Are there cases where sysfb_unregister() would need to be called even if parent
returns an error?
It could be seen as a defensive measure. Usually we want to unregister
the system framebuffer only if the native driver's device equals the
parent. But if we fail to retrieve a parent, it might be better to
unregister unconditionally. Otherwise the sysfb driver might interfere
with the native driver.
I think that would be a good idea.
Best regards
Thomas
Alex
+ if (!dev || !parent || dev == parent) {
+ sysfb_unregister();
+ disabled = true;
+ }
+ put_device(parent);
}
mutex_unlock(&disable_lock);
}
--
2.34.1
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, (HRB 36809, AG Nürnberg)
