[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] xen: do not merge reserved pages in free_heap_pages()
commit 7d3f8a2a26f2fd9c4d830820b8ad68af4e91f409 Author: Penny Zheng <Penny.Zheng@xxxxxxx> AuthorDate: Tue Aug 16 10:36:52 2022 +0800 Commit: Julien Grall <jgrall@xxxxxxxxxx> CommitDate: Wed Aug 24 10:36:20 2022 +0100 xen: do not merge reserved pages in free_heap_pages() The code in free_heap_pages() will try to merge pages with the successor/predecessor if pages are suitably aligned. So if the pages reserved are right next to the pages given to the heap allocator, free_heap_pages() will merge them, and give the reserved pages to heap allocator accidentally as a result. So in order to avoid the above scenario, this commit updates free_heap_pages() to check whether the predecessor and/or successor has PGC_static set, when trying to merge the about-to-be-freed chunk with the predecessor and/or successor. Suggested-by: Julien Grall <jgrall@xxxxxxxxxx> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx> --- xen/common/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c index 00fa24e330..bfd4150be7 100644 --- a/xen/common/page_alloc.c +++ b/xen/common/page_alloc.c @@ -1483,6 +1483,7 @@ static void free_heap_pages( /* Merge with predecessor block? */ if ( !mfn_valid(page_to_mfn(predecessor)) || !page_state_is(predecessor, free) || + (predecessor->count_info & PGC_static) || (PFN_ORDER(predecessor) != order) || (phys_to_nid(page_to_maddr(predecessor)) != node) ) break; @@ -1506,6 +1507,7 @@ static void free_heap_pages( /* Merge with successor block? */ if ( !mfn_valid(page_to_mfn(successor)) || !page_state_is(successor, free) || + (successor->count_info & PGC_static) || (PFN_ORDER(successor) != order) || (phys_to_nid(page_to_maddr(successor)) != node) ) break; -- generated by git-patchbot for /home/xen/git/xen.git#staging
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