From 338cfaad4993d3bc35a740e28981747770a65f90 Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Wed, 20 Feb 2019 22:19:36 -0800 Subject: [PATCH] slub: fix SLAB_CONSISTENCY_CHECKS + KASAN_SW_TAGS Enabling SLUB_DEBUG's SLAB_CONSISTENCY_CHECKS with KASAN_SW_TAGS triggers endless false positives during boot below due to check_valid_pointer() checks tagged pointers which have no addresses that is valid within slab pages: BUG radix_tree_node (Tainted: G B ): Freelist Pointer check fails ----------------------------------------------------------------------------- INFO: Slab objects=69 used=69 fp=0x (null) flags=0x7ffffffc000200 INFO: Object @offset=15060037153926966016 fp=0x Redzone: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 18 6b 06 00 08 80 ff d0 .........k...... Object : 18 6b 06 00 08 80 ff d0 00 00 00 00 00 00 00 00 .k.............. Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object : 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Redzone: bb bb bb bb bb bb bb bb ........ Padding: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ CPU: 0 PID: 0 Comm: swapper/0 Tainted: G B 5.0.0-rc5+ #18 Call trace: dump_backtrace+0x0/0x450 show_stack+0x20/0x2c __dump_stack+0x20/0x28 dump_stack+0xa0/0xfc print_trailer+0x1bc/0x1d0 object_err+0x40/0x50 alloc_debug_processing+0xf0/0x19c ___slab_alloc+0x554/0x704 kmem_cache_alloc+0x2f8/0x440 radix_tree_node_alloc+0x90/0x2fc idr_get_free+0x1e8/0x6d0 idr_alloc_u32+0x11c/0x2a4 idr_alloc+0x74/0xe0 worker_pool_assign_id+0x5c/0xbc workqueue_init_early+0x49c/0xd50 start_kernel+0x52c/0xac4 FIX radix_tree_node: Marking all objects used Link: http://lkml.kernel.org/r/20190209044128.3290-1-cai@lca.pw Signed-off-by: Qian Cai Reviewed-by: Andrey Konovalov Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slub.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/slub.c b/mm/slub.c index c80e6699357c..2d2830134e60 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -513,6 +513,7 @@ static inline int check_valid_pointer(struct kmem_cache *s, return 1; base = page_address(page); + object = kasan_reset_tag(object); object = restore_red_left(s, object); if (object < base || object >= base + page->objects * s->size || (object - base) % s->size) {