From a04cd1600b831a16625b45226b90a292c8f6e8d9 Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Fri, 8 Apr 2022 13:08:52 -0700 Subject: mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation. Fix a VM_BUG_ON_FOLIO(folio_nr_pages(old) != nr_pages) crash. With folios support, it is possible to have other than HPAGE_PMD_ORDER THPs, in the form of folios, in the system. Use thp_order() to correctly determine the source page order during migration. Link: https://lkml.kernel.org/r/20220404165325.1883267-1-zi.yan@sent.com Link: https://lore.kernel.org/linux-mm/20220404132908.GA785673@u2004/ Fixes: d68eccad3706 ("mm/filemap: Allow large folios to be added to the page cache") Reported-by: Naoya Horiguchi Signed-off-by: Zi Yan Cc: Matthew Wilcox Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mempolicy.c') diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a2516d31db6c..358b7c11426d 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1209,7 +1209,7 @@ static struct page *new_page(struct page *page, unsigned long start) struct page *thp; thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address, - HPAGE_PMD_ORDER); + thp_order(page)); if (!thp) return NULL; prep_transhuge_page(thp); -- cgit From 4ad099559b00ac01c3726e5c95dc3108ef47d03e Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Fri, 8 Apr 2022 13:09:07 -0700 Subject: mm/mempolicy: fix mpol_new leak in shared_policy_replace If mpol_new is allocated but not used in restart loop, mpol_new will be freed via mpol_put before returning to the caller. But refcnt is not initialized yet, so mpol_put could not do the right things and might leak the unused mpol_new. This would happen if mempolicy was updated on the shared shmem file while the sp->lock has been dropped during the memory allocation. This issue could be triggered easily with the below code snippet if there are many processes doing the below work at the same time: shmid = shmget((key_t)5566, 1024 * PAGE_SIZE, 0666|IPC_CREAT); shm = shmat(shmid, 0, 0); loop many times { mbind(shm, 1024 * PAGE_SIZE, MPOL_LOCAL, mask, maxnode, 0); mbind(shm + 128 * PAGE_SIZE, 128 * PAGE_SIZE, MPOL_DEFAULT, mask, maxnode, 0); } Link: https://lkml.kernel.org/r/20220329111416.27954-1-linmiaohe@huawei.com Fixes: 42288fe366c4 ("mm: mempolicy: Convert shared_policy mutex to spinlock") Signed-off-by: Miaohe Lin Acked-by: Michal Hocko Cc: KOSAKI Motohiro Cc: Mel Gorman Cc: [3.8] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 1 + 1 file changed, 1 insertion(+) (limited to 'mm/mempolicy.c') diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 358b7c11426d..88a74bc4cba5 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2733,6 +2733,7 @@ alloc_new: mpol_new = kmem_cache_alloc(policy_cache, GFP_KERNEL); if (!mpol_new) goto err_out; + atomic_set(&mpol_new->refcnt, 1); goto restart; } -- cgit