From: Zheng Wang <zyytlz.wz@163.com>
To: colyli@suse.de
Cc: hackerzheng666@gmail.com, kent.overstreet@gmail.com,
linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org,
alex000young@gmail.com, Zheng Wang <zyytlz.wz@163.com>
Subject: [PATCH] bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent
Date: Thu, 2 Feb 2023 23:15:04 +0800 [thread overview]
Message-ID: <20230202151504.542958-1-zyytlz.wz@163.com> (raw)
In some specific situation, the return value of __bch_btree_node_alloc may
be NULL. This may lead to poential NULL pointer dereference in caller
function like a calling chaion :
btree_split->bch_btree_node_alloc->__bch_btree_node_alloc.
Fix it by initialize return value in __bch_btree_node_alloc before return.
Fixes: cafe56359144 ("bcache: A block layer cache")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
drivers/md/bcache/btree.c | 10 ++++++----
drivers/md/bcache/super.c | 2 +-
2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 147c493a989a..35346c1d7c3c 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1090,10 +1090,12 @@ struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
struct btree *parent)
{
BKEY_PADDED(key) k;
- struct btree *b = ERR_PTR(-EAGAIN);
+ struct btree *b;
mutex_lock(&c->bucket_lock);
retry:
+ /* return ERR_PTR(-EAGAIN) when it fails */
+ b = ERR_PTR(-EAGAIN);
if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, wait))
goto err;
@@ -1138,7 +1140,7 @@ static struct btree *btree_node_alloc_replacement(struct btree *b,
{
struct btree *n = bch_btree_node_alloc(b->c, op, b->level, b->parent);
- if (!IS_ERR_OR_NULL(n)) {
+ if (!IS_ERR(n)) {
mutex_lock(&n->write_lock);
bch_btree_sort_into(&b->keys, &n->keys, &b->c->sort);
bkey_copy_key(&n->key, &b->key);
@@ -1352,7 +1354,7 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
for (i = 0; i < nodes; i++) {
new_nodes[i] = btree_node_alloc_replacement(r[i].b, NULL);
- if (IS_ERR_OR_NULL(new_nodes[i]))
+ if (IS_ERR(new_nodes[i]))
goto out_nocoalesce;
}
@@ -1669,7 +1671,7 @@ static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
if (should_rewrite) {
n = btree_node_alloc_replacement(b, NULL);
- if (!IS_ERR_OR_NULL(n)) {
+ if (!IS_ERR(n)) {
bch_btree_node_write_sync(n);
bch_btree_set_root(n);
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index ba3909bb6bea..92de714fe75e 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2088,7 +2088,7 @@ static int run_cache_set(struct cache_set *c)
err = "cannot allocate new btree root";
c->root = __bch_btree_node_alloc(c, NULL, 0, true, NULL);
- if (IS_ERR_OR_NULL(c->root))
+ if (IS_ERR(c->root))
goto err;
mutex_lock(&c->root->write_lock);
--
2.25.1
next reply other threads:[~2023-02-02 15:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-02 15:15 Zheng Wang [this message]
2023-02-02 16:23 ` [PATCH] bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent Coly Li
2023-02-02 17:19 ` Zheng Hacker
2023-02-02 20:37 ` Eric Wheeler
2023-02-03 2:08 ` Zheng Hacker
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