[PATCH bpf-next] bpf: Add more WARN_ON_ONCE checks for mismatched alloc and free

[Hou Tao <houtao@xxxxxxxxxxxxxxx>]

From: Hou Tao <houtao1@xxxxxxxxxx>

There are two possible mismatched alloc and free cases in bpf memory
allocator:
1) allocate from cache X but free by cache Y with a different unit_size
2) allocate from per-cpu cache but free by kmalloc cache or vice versa

So add more WARN_ON_ONCE checks in free_bulk() and __free_by_rcu() to
spot these mismatched alloc and free early.

Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
 kernel/bpf/memalloc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c
index 5308e386380af..63b909d277d47 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;
-- 
2.29.2