From: Vitaly Wool vitalywool@gmail.com Subject: z3fold: fix memory leak in kmem cache
Currently there is a leak in init_z3fold_page() -- it allocates handles from kmem cache even for headless pages, but then they are never used and never freed, so eventually kmem cache may get exhausted. This patch provides a fix for that.
Link: http://lkml.kernel.org/r/20190917185352.44cf285d3ebd9e64548de5de@gmail.com Signed-off-by: Vitaly Wool vitalywool@gmail.com Reported-by: Markus Linnala markus.linnala@gmail.com Tested-by: Markus Linnala markus.linnala@gmail.com Cc: Dan Streetman ddstreet@ieee.org Cc: Henry Burns henrywolfeburns@gmail.com Cc: Shakeel Butt shakeelb@google.com Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/z3fold.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
--- a/mm/z3fold.c~z3fold-fix-memory-leak-in-kmem-cache +++ a/mm/z3fold.c @@ -295,14 +295,11 @@ static void z3fold_unregister_migration( }
/* Initializes the z3fold header of a newly allocated z3fold page */ -static struct z3fold_header *init_z3fold_page(struct page *page, +static struct z3fold_header *init_z3fold_page(struct page *page, bool headless, struct z3fold_pool *pool, gfp_t gfp) { struct z3fold_header *zhdr = page_address(page); - struct z3fold_buddy_slots *slots = alloc_slots(pool, gfp); - - if (!slots) - return NULL; + struct z3fold_buddy_slots *slots;
INIT_LIST_HEAD(&page->lru); clear_bit(PAGE_HEADLESS, &page->private); @@ -310,6 +307,12 @@ static struct z3fold_header *init_z3fold clear_bit(NEEDS_COMPACTING, &page->private); clear_bit(PAGE_STALE, &page->private); clear_bit(PAGE_CLAIMED, &page->private); + if (headless) + return zhdr; + + slots = alloc_slots(pool, gfp); + if (!slots) + return NULL;
spin_lock_init(&zhdr->page_lock); kref_init(&zhdr->refcount); @@ -930,7 +933,7 @@ retry: if (!page) return -ENOMEM;
- zhdr = init_z3fold_page(page, pool, gfp); + zhdr = init_z3fold_page(page, bud == HEADLESS, pool, gfp); if (!zhdr) { __free_page(page); return -ENOMEM; _