Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - MM remainders

 - various misc things

 - kcov updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (27 commits)
  lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
  hexagon: drop the unused variable zero_page_mask
  hexagon: fix printk format warning in setup.c
  mm: fix oom_kill event handling
  treewide: use PHYS_ADDR_MAX to avoid type casting ULLONG_MAX
  mm: use octal not symbolic permissions
  ipc: use new return type vm_fault_t
  sysvipc/sem: mitigate semnum index against spectre v1
  fault-injection: reorder config entries
  arm: port KCOV to arm
  sched/core / kcov: avoid kcov_area during task switch
  kcov: prefault the kcov_area
  kcov: ensure irq code sees a valid area
  kernel/relay.c: change return type to vm_fault_t
  exofs: avoid VLA in structures
  coredump: fix spam with zero VMA process
  fat: use fat_fs_error() instead of BUG_ON() in __fat_get_block()
  proc: skip branch in /proc/*/* lookup
  mremap: remove LATENCY_LIMIT from mremap to reduce the number of TLB shootdowns
  mm/memblock: add missing include <linux/bootmem.h>
  ...

1 files changed, 34 insertions, 3 deletions

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 98dcdc352062..890b1f04a03a 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -136,6 +136,7 @@ void slab_init_memcg_params(struct kmem_cache *s)
 	s->memcg_params.root_cache = NULL;
 	RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
 	INIT_LIST_HEAD(&s->memcg_params.children);
+	s->memcg_params.dying = false;
 }
 
 static int init_memcg_params(struct kmem_cache *s,
@@ -608,7 +609,7 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
 	 * The memory cgroup could have been offlined while the cache
 	 * creation work was pending.
 	 */
-	if (memcg->kmem_state != KMEM_ONLINE)
+	if (memcg->kmem_state != KMEM_ONLINE || root_cache->memcg_params.dying)
 		goto out_unlock;
 
 	idx = memcg_cache_id(memcg);
@@ -712,6 +713,9 @@ void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
 	    WARN_ON_ONCE(s->memcg_params.deact_fn))
 		return;
 
+	if (s->memcg_params.root_cache->memcg_params.dying)
+		return;
+
 	/* pin memcg so that @s doesn't get destroyed in the middle */
 	css_get(&s->memcg_params.memcg->css);
 
@@ -823,11 +827,36 @@ static int shutdown_memcg_caches(struct kmem_cache *s)
 		return -EBUSY;
 	return 0;
 }
+
+static void flush_memcg_workqueue(struct kmem_cache *s)
+{
+	mutex_lock(&slab_mutex);
+	s->memcg_params.dying = true;
+	mutex_unlock(&slab_mutex);
+
+	/*
+	 * SLUB deactivates the kmem_caches through call_rcu_sched. Make
+	 * sure all registered rcu callbacks have been invoked.
+	 */
+	if (IS_ENABLED(CONFIG_SLUB))
+		rcu_barrier_sched();
+
+	/*
+	 * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB
+	 * deactivates the memcg kmem_caches through workqueue. Make sure all
+	 * previous workitems on workqueue are processed.
+	 */
+	flush_workqueue(memcg_kmem_cache_wq);
+}
 #else
 static inline int shutdown_memcg_caches(struct kmem_cache *s)
 {
 	return 0;
 }
+
+static inline void flush_memcg_workqueue(struct kmem_cache *s)
+{
+}
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 
 void slab_kmem_cache_release(struct kmem_cache *s)
@@ -845,6 +874,8 @@ void kmem_cache_destroy(struct kmem_cache *s)
 	if (unlikely(!s))
 		return;
 
+	flush_memcg_workqueue(s);
+
 	get_online_cpus();
 	get_online_mems();
 
@@ -1212,9 +1243,9 @@ void cache_random_seq_destroy(struct kmem_cache *cachep)
 
 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
 #ifdef CONFIG_SLAB
-#define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR)
+#define SLABINFO_RIGHTS (0600)
 #else
-#define SLABINFO_RIGHTS S_IRUSR
+#define SLABINFO_RIGHTS (0400)
 #endif
 
 static void print_slabinfo_header(struct seq_file *m)