https://git.reactos.org/?p=reactos.git;a=commitdiff;h=3f601122bce70808381d2255abb938f9369f2eb5
commit 3f601122bce70808381d2255abb938f9369f2eb5 Author: Victor Perevertkin <[email protected]> AuthorDate: Mon Jun 14 04:50:01 2021 +0300 Commit: Jérôme Gardou <[email protected]> CommitDate: Wed Jun 16 12:14:27 2021 +0200 [NTOS:MM] Fix placing entries into MmNonPagedPoolFreeListHead When freeing pages, free page entries with pages num == 3 were incorrectly treated as entries with pages num >= 4 and thus their re-insertion was not triggered. That lead to non paged pool fragmentation (can be triggered by kmtest:ExPools, for example) Also, altered the index acquisition code for MmNonPagedPoolFreeList entries so it looks more clear --- ntoskrnl/mm/ARM3/pool.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/ntoskrnl/mm/ARM3/pool.c b/ntoskrnl/mm/ARM3/pool.c index 5a406e166d8..fe8d6cd1a74 100644 --- a/ntoskrnl/mm/ARM3/pool.c +++ b/ntoskrnl/mm/ARM3/pool.c @@ -680,8 +680,7 @@ MiAllocatePoolPages(IN POOL_TYPE PoolType, // // Allocations of less than 4 pages go into their individual buckets // - i = SizeInPages - 1; - if (i >= MI_MAX_FREE_PAGE_LISTS) i = MI_MAX_FREE_PAGE_LISTS - 1; + i = min(SizeInPages, MI_MAX_FREE_PAGE_LISTS) - 1; // // Loop through all the free page lists based on the page index @@ -738,8 +737,7 @@ MiAllocatePoolPages(IN POOL_TYPE PoolType, if (FreeEntry->Size != 0) { /* Check which list to insert this entry into */ - i = FreeEntry->Size - 1; - if (i >= MI_MAX_FREE_PAGE_LISTS) i = MI_MAX_FREE_PAGE_LISTS - 1; + i = min(FreeEntry->Size, MI_MAX_FREE_PAGE_LISTS) - 1; /* Insert the entry into the free list head, check for prot. pool */ if (MmProtectFreedNonPagedPool) @@ -1176,11 +1174,11 @@ MiFreePoolPages(IN PVOID StartingVa) } // - // Check if the entry is small enough to be indexed on a free list + // Check if the entry is small enough (1-3 pages) to be indexed on a free list // If it is, we'll want to re-insert it, since we're about to // collapse our pages on top of it, which will change its count // - if (FreeEntry->Size < (MI_MAX_FREE_PAGE_LISTS - 1)) + if (FreeEntry->Size < MI_MAX_FREE_PAGE_LISTS) { /* Remove the item from the list, depending if pool is protected */ if (MmProtectFreedNonPagedPool) @@ -1196,8 +1194,7 @@ MiFreePoolPages(IN PVOID StartingVa) // // And now find the new appropriate list to place it in // - i = (ULONG)(FreeEntry->Size - 1); - if (i >= MI_MAX_FREE_PAGE_LISTS) i = MI_MAX_FREE_PAGE_LISTS - 1; + i = min(FreeEntry->Size, MI_MAX_FREE_PAGE_LISTS) - 1; /* Insert the entry into the free list head, check for prot. pool */ if (MmProtectFreedNonPagedPool) @@ -1228,8 +1225,7 @@ MiFreePoolPages(IN PVOID StartingVa) // // Find the appropriate list we should be on // - i = FreeEntry->Size - 1; - if (i >= MI_MAX_FREE_PAGE_LISTS) i = MI_MAX_FREE_PAGE_LISTS - 1; + i = min(FreeEntry->Size, MI_MAX_FREE_PAGE_LISTS) - 1; /* Insert the entry into the free list head, check for prot. pool */ if (MmProtectFreedNonPagedPool)
