can: Before we use pstate, we should check if it is NULL.

hujun260 · xiaoxiang781216 · commit e1b9144e7190 · 2024-09-05T21:25:22.000+08:00
Signed-off-by: hujun5 &lt;hujun5@xiaomi.com&gt;
diff --git a/net/can/can_recvmsg.c b/net/can/can_recvmsg.c
@@ -369,14 +369,15 @@ static uint16_t can_recvfrom_eventhandler(FAR struct net_driver_s *dev,
                                           FAR void *pvpriv, uint16_t flags)
 {
   struct can_recvfrom_s *pstate = pvpriv;
-#if defined(CONFIG_NET_CANPROTO_OPTIONS) || defined(CONFIG_NET_TIMESTAMP)
-  struct can_conn_s *conn = pstate->pr_conn;
-#endif
 
   /* 'priv' might be null in some race conditions (?) */
 
   if (pstate)
     {
+#if defined(CONFIG_NET_CANPROTO_OPTIONS) || defined(CONFIG_NET_TIMESTAMP)
+      struct can_conn_s *conn = pstate->pr_conn;
+#endif
+
       if ((flags & CAN_NEWDATA) != 0)
         {
           /* If a new packet is available, check receive filters

Original file line number	Diff line number	Diff line change
`@@ -369,14 +369,15 @@ static uint16_t can_recvfrom_eventhandler(FAR struct net_driver_s *dev,`
`369`	`369`	`FAR void *pvpriv, uint16_t flags)`
`370`	`370`	`{`
`371`	`371`	`struct can_recvfrom_s *pstate = pvpriv;`
`372`		`-#if defined(CONFIG_NET_CANPROTO_OPTIONS) \|\| defined(CONFIG_NET_TIMESTAMP)`
`373`		`- struct can_conn_s *conn = pstate->pr_conn;`
`374`		`-#endif`
`375`	`372`
`376`	`373`	`/* 'priv' might be null in some race conditions (?) */`
`377`	`374`
`378`	`375`	`if (pstate)`
`379`	`376`	`{`
	`377`	`+#if defined(CONFIG_NET_CANPROTO_OPTIONS) \|\| defined(CONFIG_NET_TIMESTAMP)`
	`378`	`+ struct can_conn_s *conn = pstate->pr_conn;`
	`379`	`+#endif`
	`380`	`+`
`380`	`381`	`if ((flags & CAN_NEWDATA) != 0)`
`381`	`382`	`{`
`382`	`383`	`/* If a new packet is available, check receive filters`