[ros-diffs] [reactos] 01/01: [NTOS:MM] MmPurgeSegment: Fix missing MmDereferenceSegment cleanup (#7509)

[Thamatip Chitpong]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=d52031a4f1381282891f9…

commit d52031a4f1381282891f9f97b0c5812356aa83dc
Author:     Thamatip Chitpong <thamatip.chitpong(a)reactos.org>
AuthorDate: Tue Nov 19 11:17:41 2024 +0700
Commit:     GitHub <noreply(a)github.com>
CommitDate: Tue Nov 19 11:17:41 2024 +0700

    [NTOS:MM] MmPurgeSegment: Fix missing MmDereferenceSegment cleanup (#7509)
    
    MiGrabDataSection adds a refcount. There is a missing MmDereferenceSegment cleanup in
case of range check error.
    Fix that by moving MiGrabDataSection calling code to after range check.
---
 ntoskrnl/mm/section.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/ntoskrnl/mm/section.c b/ntoskrnl/mm/section.c
index f935e6f30c1..50609bac71c 100644
--- a/ntoskrnl/mm/section.c
+++ b/ntoskrnl/mm/section.c
@@ -4838,13 +4838,6 @@ MmPurgeSegment(
     LARGE_INTEGER PurgeStart, PurgeEnd;
     PMM_SECTION_SEGMENT Segment;
 
-    Segment = MiGrabDataSection(SectionObjectPointer);
-    if (!Segment)
-    {
-        /* Nothing to purge */
-        return TRUE;
-    }
-
     PurgeStart.QuadPart = Offset ? Offset->QuadPart : 0LL;
     if (Length && Offset)
     {
@@ -4852,6 +4845,13 @@ MmPurgeSegment(
             return FALSE;
     }
 
+    Segment = MiGrabDataSection(SectionObjectPointer);
+    if (!Segment)
+    {
+        /* Nothing to purge */
+        return TRUE;
+    }
+
     MmLockSectionSegment(Segment);
 
     if (!Length || !Offset)