[reactos] 01/01: [NTOS:PNP] Fix bug causing all devices be considered as already existing

[Sophie Lemos]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=29a706fc5ad0a1b169688b...

commit 29a706fc5ad0a1b169688b86d19f12ef1552c07a
Author:     Sophie Lemos [e-mail]
AuthorDate: Fri May 26 17:42:36 2023 +0100
Commit:     Stanislav Motylkov [e-mail]
CommitDate: Sun Jun 11 13:13:11 2023 +0300

[NTOS:PNP] Fix bug causing all devices be considered as already existing

We should compare against DeviceObject as DeviceInstance is never NULL.
    Fix a resource leak as well. The bug CORE-18983 seems to lay somewhere
    else though, I just stumbled upon this one while researching it.

Note there is a BSOD in the PnP manager on reboot after the driver
    installation failure, but it seems it was uncovered by the fix
    as opposed to caused by it.
---
 ntoskrnl/io/pnpmgr/plugplay.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/ntoskrnl/io/pnpmgr/plugplay.c b/ntoskrnl/io/pnpmgr/plugplay.c
index 46585458b84..461328c8651 100644
--- a/ntoskrnl/io/pnpmgr/plugplay.c
+++ b/ntoskrnl/io/pnpmgr/plugplay.c
@@ -218,15 +218,14 @@ IopInitializeDevice(

/* Leave, if the device already exists */
     DeviceObject = IopGetDeviceObjectFromDeviceInstance(&DeviceInstance);
-    if (DeviceInstance.Buffer != NULL)
+    if (DeviceObject != NULL)
     {
         DPRINT1("Device %wZ already exists!\n", &DeviceInstance);
+        ObDereferenceObject(DeviceObject);
         Status = STATUS_SUCCESS;
         goto done;
     }

-    ObDereferenceObject(DeviceObject);
-
     DPRINT("Device %wZ does not exist!\n", &DeviceInstance);

/* Create a device node for the device instance */