slub: don't panic for memcg kmem cache creation failure

mainline inclusion
from mainline-v5.3-rc1
commit cb097cd4
category: bugfix
bugzilla: 18470
CVE: NA

-------------------------------------------------

Currently for CONFIG_SLUB, if a memcg kmem cache creation is failed and
the corresponding root kmem cache has SLAB_PANIC flag, the kernel will
be crashed.  This is unnecessary as the kernel can handle the creation
failures of memcg kmem caches.  Additionally CONFIG_SLAB does not
implement this behavior.  So, to keep the behavior consistent between
SLAB and SLUB, removing the panic for memcg kmem cache creation
failures.  The root kmem cache creation failure for SLAB_PANIC correctly
panics for both SLAB and SLUB.

Link: http://lkml.kernel.org/r/20190619232514.58994-1-shakeelb@google.comReported-by: NDave Hansen <dave.hansen@intel.com>
Signed-off-by: NShakeel Butt <shakeelb@google.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ntongtiangen <tongtiangen@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

mm/slub.c

@@ -3610,10 +3610,6 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
 
 	free_kmem_cache_nodes(s);
 error:
-	if (flags & SLAB_PANIC)
-		panic("Cannot create slab %s size=%u realsize=%u order=%u offset=%u flags=%lx\n",
-		      s->name, s->size, s->size,
-		      oo_order(s->oo), s->offset, (unsigned long)flags);
 	return -EINVAL;
 }