[reactos] 01/01: [NTOSKRNL] Don't call AcquireForLazyWrite with the master lock held

[Pierre Schweitzer]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=1435ff95b4a1f369a2575…

commit 1435ff95b4a1f369a2575eecafe5981896ba4877
Author:     Pierre Schweitzer <pierre(a)reactos.org>
AuthorDate: Fri Dec 21 08:44:14 2018 +0100
Commit:     Pierre Schweitzer <pierre(a)reactos.org>
CommitDate: Fri Dec 21 08:46:40 2018 +0100

    [NTOSKRNL] Don't call AcquireForLazyWrite with the master lock held
    
    This incorrect behavior was leading to a call at too high IRQL for paged code.
    This was triggered by MS FastFAT.
    
    ReleaseFromLazyWrite call was already correctly called to that regard.
    
    CORE-11819
---
 ntoskrnl/cc/view.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/ntoskrnl/cc/view.c b/ntoskrnl/cc/view.c
index 81a1dac801..d64496595f 100644
--- a/ntoskrnl/cc/view.c
+++ b/ntoskrnl/cc/view.c
@@ -222,18 +222,19 @@ CcRosFlushDirtyPages (
             continue;
         }
 
+        ASSERT(current->Dirty);
+
+        KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
+
         Locked = current->SharedCacheMap->Callbacks->AcquireForLazyWrite(
                      current->SharedCacheMap->LazyWriteContext, Wait);
         if (!Locked)
         {
+            OldIrql = KeAcquireQueuedSpinLock(LockQueueMasterLock);
             CcRosVacbDecRefCount(current);
             continue;
         }
 
-        ASSERT(current->Dirty);
-
-        KeReleaseQueuedSpinLock(LockQueueMasterLock, OldIrql);
-
         Status = CcRosFlushVacb(current);
 
         current->SharedCacheMap->Callbacks->ReleaseFromLazyWrite(