Re: [PATCH] slab: store tagged freelist for off-slab slabmgmt

[Qian Cai]

On Wed, 2019-04-03 at 13:23 +0200, Andrey Konovalov wrote:
> On Wed, Apr 3, 2019 at 4:29 AM Qian Cai <cai@xxxxxx> wrote:
> > 
> > The commit 51dedad06b5f ("kasan, slab: make freelist stored without
> > tags") calls kasan_reset_tag() for off-slab slab management object
> > leading to freelist being stored non-tagged. However, cache_grow_begin()
> > -> alloc_slabmgmt() -> kmem_cache_alloc_node() which assigns a tag for
> > the address and stores in the shadow address. As the result, it causes
> > endless errors below during boot due to drain_freelist() ->
> > slab_destroy() -> kasan_slab_free() which compares already untagged
> > freelist against the stored tag in the shadow address. Since off-slab
> > slab management object freelist is such a special case, so just store it
> > tagged. Non-off-slab management object freelist is still stored untagged
> > which has not been assigned a tag and should not cause any other
> > troubles with this inconsistency.
> 
> Hi Qian,
> 
> Could you share the config (or other steps) you used to reproduce this?

https://git.sr.ht/~cai/linux-debug/blob/master/config

Additional command-line option to boot:

page_poison=on crashkernel=768M earlycon page_owner=on numa_balancing=enable
systemd.unified_cgroup_hierarchy=1 debug_guardpage_minorder=1