drm/mediatek: Add missing IS_ERR check for ovl_adaptor platform devicegrafted

platform_device_register_data() can fail and return an ERR_PTR, but the
return value is used without checking, leading to an invalid pointer
being stored in ddp_comp[].dev and passed to component_match_add() and
mtk_ddp_comp_init(), which could result in a kernel crash.

Add an IS_ERR() check to jump to the error handling path on failure.

Fixes: 0d9eee9118b7 ("drm/mediatek: Add drm ovl_adaptor sub driver for MT8195")
Cc: stable@vger.kernel.org
Signed-off-by: Haojie Li <lihaojie@kylinos.cn>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/linux-mediatek/patch/20260825100845.438893-1-lihaojie@kylinos.cn/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

1 files changed, 159 insertions, 0 deletions

diff --git a/include/net/llc.h b/include/net/llc.h
new file mode 100644
index 000000000..029ba8a22
--- /dev/null
+++ b/include/net/llc.h
@@ -0,0 +1,159 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LLC_H
+#define LLC_H
+/*
+ * Copyright (c) 1997 by Procom Technology, Inc.
+ * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
+ */
+
+#include <linux/if.h>
+#include <linux/if_ether.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/rculist_nulls.h>
+#include <linux/hash.h>
+#include <linux/jhash.h>
+
+#include <linux/atomic.h>
+
+struct net_device;
+struct packet_type;
+struct sk_buff;
+
+struct llc_addr {
+	unsigned char lsap;
+	unsigned char mac[IFHWADDRLEN];
+};
+
+#define LLC_SAP_STATE_INACTIVE	1
+#define LLC_SAP_STATE_ACTIVE	2
+
+#define LLC_SK_DEV_HASH_BITS 6
+#define LLC_SK_DEV_HASH_ENTRIES (1<<LLC_SK_DEV_HASH_BITS)
+
+#define LLC_SK_LADDR_HASH_BITS 6
+#define LLC_SK_LADDR_HASH_ENTRIES (1<<LLC_SK_LADDR_HASH_BITS)
+
+/**
+ * struct llc_sap - Defines the SAP component
+ *
+ * @station - station this sap belongs to
+ * @state - sap state
+ * @p_bit - only lowest-order bit used
+ * @f_bit - only lowest-order bit used
+ * @laddr - SAP value in this 'lsap'
+ * @node - entry in station sap_list
+ * @sk_list - LLC sockets this one manages
+ */
+struct llc_sap {
+	unsigned char	 state;
+	unsigned char	 p_bit;
+	unsigned char	 f_bit;
+	refcount_t		 refcnt;
+	int		 (*rcv_func)(struct sk_buff *skb,
+				     struct net_device *dev,
+				     struct packet_type *pt,
+				     struct net_device *orig_dev);
+	struct llc_addr	 laddr;
+	struct list_head node;
+	spinlock_t sk_lock;
+	int sk_count;
+	struct hlist_nulls_head sk_laddr_hash[LLC_SK_LADDR_HASH_ENTRIES];
+	struct hlist_head sk_dev_hash[LLC_SK_DEV_HASH_ENTRIES];
+	struct rcu_head rcu;
+};
+
+static inline
+struct hlist_head *llc_sk_dev_hash(struct llc_sap *sap, int ifindex)
+{
+	u32 bucket = hash_32(ifindex, LLC_SK_DEV_HASH_BITS);
+
+	return &sap->sk_dev_hash[bucket];
+}
+
+static inline
+u32 llc_sk_laddr_hashfn(struct llc_sap *sap, const struct llc_addr *laddr)
+{
+	return hash_32(jhash(laddr->mac, sizeof(laddr->mac), 0),
+		       LLC_SK_LADDR_HASH_BITS);
+}
+
+static inline
+struct hlist_nulls_head *llc_sk_laddr_hash(struct llc_sap *sap,
+					   const struct llc_addr *laddr)
+{
+	return &sap->sk_laddr_hash[llc_sk_laddr_hashfn(sap, laddr)];
+}
+
+#define LLC_DEST_INVALID         0      /* Invalid LLC PDU type */
+#define LLC_DEST_SAP             1      /* Type 1 goes here */
+#define LLC_DEST_CONN            2      /* Type 2 goes here */
+
+extern struct list_head llc_sap_list;
+
+int llc_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
+	    struct net_device *orig_dev);
+
+int llc_mac_hdr_init(struct sk_buff *skb, const unsigned char *sa,
+		     const unsigned char *da);
+
+void llc_add_pack(int type,
+		  void (*handler)(struct llc_sap *sap, struct sk_buff *skb));
+void llc_remove_pack(int type);
+
+void llc_set_station_handler(void (*handler)(struct sk_buff *skb));
+
+struct llc_sap *llc_sap_open(unsigned char lsap,
+			     int (*rcv)(struct sk_buff *skb,
+					struct net_device *dev,
+					struct packet_type *pt,
+					struct net_device *orig_dev));
+static inline void llc_sap_hold(struct llc_sap *sap)
+{
+	refcount_inc(&sap->refcnt);
+}
+
+static inline bool llc_sap_hold_safe(struct llc_sap *sap)
+{
+	return refcount_inc_not_zero(&sap->refcnt);
+}
+
+void llc_sap_close(struct llc_sap *sap);
+
+static inline void llc_sap_put(struct llc_sap *sap)
+{
+	if (refcount_dec_and_test(&sap->refcnt))
+		llc_sap_close(sap);
+}
+
+struct llc_sap *llc_sap_find(unsigned char sap_value);
+
+int llc_build_and_send_ui_pkt(struct llc_sap *sap, struct sk_buff *skb,
+			      const unsigned char *dmac, unsigned char dsap);
+
+void llc_sap_handler(struct llc_sap *sap, struct sk_buff *skb);
+void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb);
+
+void llc_station_init(void);
+void llc_station_exit(void);
+
+#ifdef CONFIG_PROC_FS
+int llc_proc_init(void);
+void llc_proc_exit(void);
+#else
+#define llc_proc_init()	(0)
+#define llc_proc_exit()	do { } while(0)
+#endif /* CONFIG_PROC_FS */
+#ifdef CONFIG_SYSCTL
+int llc_sysctl_init(void);
+void llc_sysctl_exit(void);
+
+extern int sysctl_llc2_ack_timeout;
+extern int sysctl_llc2_busy_timeout;
+extern int sysctl_llc2_p_timeout;
+extern int sysctl_llc2_rej_timeout;
+#else
+#define llc_sysctl_init() (0)
+#define llc_sysctl_exit() do { } while(0)
+#endif /* CONFIG_SYSCTL */
+#endif /* LLC_H */