Messages in this thread | | | From | Andrey Konovalov <> | Date | Tue, 12 Feb 2019 14:26:58 +0100 | Subject | Re: [PATCH 5/5] kasan, slub: fix conflicts with CONFIG_SLAB_FREELIST_HARDENED |
| |
On Tue, Feb 12, 2019 at 3:43 AM Qian Cai <cai@lca.pw> wrote: > > > > On 2/11/19 4:59 PM, Andrey Konovalov wrote: > > CONFIG_SLAB_FREELIST_HARDENED hashes freelist pointer with the address > > of the object where the pointer gets stored. With tag based KASAN we don't > > account for that when building freelist, as we call set_freepointer() with > > the first argument untagged. This patch changes the code to properly > > propagate tags throughout the loop. > > > > Reported-by: Qian Cai <cai@lca.pw> > > Signed-off-by: Andrey Konovalov <andreyknvl@google.com> > > --- > > mm/slub.c | 20 +++++++------------- > > 1 file changed, 7 insertions(+), 13 deletions(-) > > > > diff --git a/mm/slub.c b/mm/slub.c > > index ce874a5c9ee7..0d32f8d30752 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -303,11 +303,6 @@ static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) > > __p < (__addr) + (__objects) * (__s)->size; \ > > __p += (__s)->size) > > > > -#define for_each_object_idx(__p, __idx, __s, __addr, __objects) \ > > - for (__p = fixup_red_left(__s, __addr), __idx = 1; \ > > - __idx <= __objects; \ > > - __p += (__s)->size, __idx++) > > - > > /* Determine object index from a given position */ > > static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr) > > { > > @@ -1655,17 +1650,16 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) > > shuffle = shuffle_freelist(s, page); > > > > if (!shuffle) { > > - for_each_object_idx(p, idx, s, start, page->objects) { > > - if (likely(idx < page->objects)) { > > - next = p + s->size; > > - next = setup_object(s, page, next); > > - set_freepointer(s, p, next); > > - } else > > - set_freepointer(s, p, NULL); > > - } > > start = fixup_red_left(s, start); > > start = setup_object(s, page, start); > > page->freelist = start; > > + for (idx = 0, p = start; idx < page->objects - 1; idx++) { > > + next = p + s->size; > > + next = setup_object(s, page, next); > > + set_freepointer(s, p, next); > > + p = next; > > + } > > + set_freepointer(s, p, NULL); > > } > > > > page->inuse = page->objects; > > > > Well, this one patch does not work here, as it throws endless errors below > during boot. Still need this patch to fix it.
Hm, did you apply all 6 patches (the one that you sent and these five)?
> > https://marc.info/?l=linux-mm&m=154955366113951&w=2 > > [ 85.744772] BUG kmemleak_object (Tainted: G B L ): Freepointer > corrupt > [ 85.744776] > ----------------------------------------------------------------------------- > [ 85.744776] > [ 85.744788] INFO: Allocated in create_object+0x88/0x9c8 age=2564 cpu=153 pid=1 > [ 85.744797] kmem_cache_alloc+0x39c/0x4ec > [ 85.744803] create_object+0x88/0x9c8 > [ 85.744811] kmemleak_alloc+0xbc/0x180 > [ 85.744818] kmem_cache_alloc+0x3ec/0x4ec > [ 85.744825] acpi_ut_create_generic_state+0x64/0xc4 > [ 85.744832] acpi_ut_create_pkg_state+0x24/0x1c8 > [ 85.744840] acpi_ut_walk_package_tree+0x268/0x564 > [ 85.744848] acpi_ns_init_one_package+0x80/0x114 > [ 85.744856] acpi_ns_init_one_object+0x214/0x3d8 > [ 85.744862] acpi_ns_walk_namespace+0x288/0x384 > [ 85.744869] acpi_walk_namespace+0xac/0xe8 > [ 85.744877] acpi_ns_initialize_objects+0x50/0x98 > [ 85.744883] acpi_load_tables+0xac/0x120 > [ 85.744891] acpi_init+0x128/0x850 > [ 85.744898] do_one_initcall+0x3ac/0x8c0 > [ 85.744906] kernel_init_freeable+0xcdc/0x1104 > [ 85.744916] INFO: Freed in free_object_rcu+0x200/0x228 age=3 cpu=153 pid=0 > [ 85.744923] free_object_rcu+0x200/0x228 > [ 85.744931] rcu_process_callbacks+0xb00/0x12c0 > [ 85.744937] __do_softirq+0x644/0xfd0 > [ 85.744944] irq_exit+0x29c/0x370 > [ 85.744952] __handle_domain_irq+0xe0/0x1c4 > [ 85.744958] gic_handle_irq+0x1c4/0x3b0 > [ 85.744964] el1_irq+0xb0/0x140 > [ 85.744971] arch_cpu_idle+0x26c/0x594 > [ 85.744978] default_idle_call+0x44/0x5c > [ 85.744985] do_idle+0x180/0x260 > [ 85.744993] cpu_startup_entry+0x24/0x28 > [ 85.745001] secondary_start_kernel+0x36c/0x440 > [ 85.745009] INFO: Slab 0x(____ptrval____) objects=91 used=0 > fp=0x(____ptrval____) flags=0x17ffffffc000200 > [ 85.745015] INFO: Object 0x(____ptrval____) @offset=35296 fp=0x(____ptrval____) > > kkkkk4.226750] Redzone (____ptrval____): bb bb bb bb bb bb bb bb bb bb bb bb bb > bb bb bb ................ > [ 84.22[ 84.226765] ORedzone (____ptrptrval____): 5a worker/223:0 Tainted: G > B L 5.0.0-rc6+ #36 > [ 84.226790] Hardware name: HPE Apollo 70 /C01_APACHE_MB , > BIOS L50_5.13_1.0.6 07/10/2018 > [ 84.226798] Workqueue: events free_obj_work > [ 84.226802] Call trace: > [ 84.226809] dump_backtrace+0x0/0x450 > [ 84.226815] show_stack+0x20/0x2c > [ 84.226822] __dump_stack+0x20/0x28 > [ 84.226828] dump_stack+0xa0/0xfc > [ 84.226835] print_trailer+0x1a8/0x1bc > [ 84.226842] object_err+0x40/0x50 > [ 84.226848] check_object+0x214/0x2b8 > [ 84.226854] __free_slab+0x9c/0x31c > [ 84.226860] discard_slab+0x78/0xa8 > [ 84.226866] kmem_cache_free+0x99c/0x9f0 > [ 84.226873] free_obj_work+0x92c/0xa44 > [ 84.226879] process_one_work+0x894/0x1280 > [ 84.226885] worker_thread+0x684/0xa1c > [ 84.226892] kthread+0x2cc/0x2e8 > [ 84.226898] ret_from_fork+0x10/0x18 > [ 84.229197]
| |