diff options
Diffstat (limited to '')
| -rw-r--r-- | kernel/bpf/memalloc.c | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 85f9501ff6..aa0fbf000a 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -340,6 +340,7 @@ static void free_bulk(struct bpf_mem_cache *c) int cnt; WARN_ON_ONCE(tgt->unit_size != c->unit_size); + WARN_ON_ONCE(tgt->percpu_size != c->percpu_size); do { inc_active(c, &flags); @@ -365,6 +366,9 @@ static void __free_by_rcu(struct rcu_head *head) struct bpf_mem_cache *tgt = c->tgt; struct llist_node *llnode; + WARN_ON_ONCE(tgt->unit_size != c->unit_size); + WARN_ON_ONCE(tgt->percpu_size != c->percpu_size); + llnode = llist_del_all(&c->waiting_for_gp); if (!llnode) goto out; @@ -501,6 +505,9 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) struct obj_cgroup *objcg = NULL; int cpu, i, unit_size, percpu_size = 0; + /* room for llist_node and per-cpu pointer */ + if (percpu) + percpu_size = LLIST_NODE_SZ + sizeof(void *); ma->percpu = percpu; if (size) { @@ -508,10 +515,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) if (!pc) return -ENOMEM; - if (percpu) - /* room for llist_node and per-cpu pointer */ - percpu_size = LLIST_NODE_SZ + sizeof(void *); - else + if (!percpu) size += LLIST_NODE_SZ; /* room for llist_node */ unit_size = size; @@ -532,10 +536,6 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) return 0; } - /* size == 0 && percpu is an invalid combination */ - if (WARN_ON_ONCE(percpu)) - return -EINVAL; - pcc = __alloc_percpu_gfp(sizeof(*cc), 8, GFP_KERNEL); if (!pcc) return -ENOMEM; @@ -548,6 +548,7 @@ int bpf_mem_alloc_init(struct bpf_mem_alloc *ma, int size, bool percpu) c = &cc->cache[i]; c->unit_size = sizes[i]; c->objcg = objcg; + c->percpu_size = percpu_size; c->tgt = c; init_refill_work(c); @@ -742,12 +743,17 @@ static void notrace *unit_alloc(struct bpf_mem_cache *c) } } local_dec(&c->active); - local_irq_restore(flags); WARN_ON(cnt < 0); if (cnt < c->low_watermark) irq_work_raise(c); + /* Enable IRQ after the enqueue of irq work completes, so irq work + * will run after IRQ is enabled and free_llist may be refilled by + * irq work before other task preempts current task. + */ + local_irq_restore(flags); + return llnode; } @@ -783,11 +789,16 @@ static void notrace unit_free(struct bpf_mem_cache *c, void *ptr) llist_add(llnode, &c->free_llist_extra); } local_dec(&c->active); - local_irq_restore(flags); if (cnt > c->high_watermark) /* free few objects from current cpu into global kmalloc pool */ irq_work_raise(c); + /* Enable IRQ after irq_work_raise() completes, otherwise when current + * task is preempted by task which does unit_alloc(), unit_alloc() may + * return NULL unexpectedly because irq work is already pending but can + * not been triggered and free_llist can not be refilled timely. + */ + local_irq_restore(flags); } static void notrace unit_free_rcu(struct bpf_mem_cache *c, void *ptr) @@ -805,10 +816,10 @@ static void notrace unit_free_rcu(struct bpf_mem_cache *c, void *ptr) llist_add(llnode, &c->free_llist_extra_rcu); } local_dec(&c->active); - local_irq_restore(flags); if (!atomic_read(&c->call_rcu_in_progress)) irq_work_raise(c); + local_irq_restore(flags); } /* Called from BPF program or from sys_bpf syscall. |