nbd: Fix memory leak in nbd_add_socket (579dd91a) · Commits · 戴 / test

When adding first socket to nbd, if nsock's allocation failed, the data structure member "config->socks" was reallocated, but the data structure member "config->num_connections" was not updated. A memory leak will occur then because the function "nbd_config_put" will free "config->socks" only when "config->num_connections" is not zero. Fixes: ("nbd: prevent memory leak") Reported-by:

<syzbot+934037347002901b8d2a@syzkaller.appspotmail.com> Signed-off-by:

Zheng Bin <zhengbin13@huawei.com> Reviewed-by:

Eric Biggers <ebiggers@google.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

drivers/block/nbd.c

+15 −10

Original line number	Diff line number	Diff line
		@@ -1033,25 +1033,26 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
		test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
		dev_err(disk_to_dev(nbd->disk),
		"Device being setup by another task");
		sockfd_put(sock);
		return -EBUSY;
		err = -EBUSY;
		goto put_socket;
		}

		nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
		if (!nsock) {
		err = -ENOMEM;
		goto put_socket;
		}

		socks = krealloc(config->socks, (config->num_connections + 1) *
		sizeof(struct nbd_sock *), GFP_KERNEL);
		if (!socks) {
		sockfd_put(sock);
		return -ENOMEM;
		kfree(nsock);
		err = -ENOMEM;
		goto put_socket;
		}

		config->socks = socks;

		nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
		if (!nsock) {
		sockfd_put(sock);
		return -ENOMEM;
		}

		nsock->fallback_index = -1;
		nsock->dead = false;
		mutex_init(&nsock->tx_lock);
		@@ -1063,6 +1064,10 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
		atomic_inc(&config->live_connections);

		return 0;

		put_socket:
		sockfd_put(sock);
		return err;
		}

		static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)

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