Steps to reproduce:

1. Tested on Solaris 11/SPARC
2. Install agent:

   pkg install -g file:////export/home/src/zabbix_agent-5.0.10-solaris-11-sparc-openssl.p5p zabbix-agent
   

3. Configure Agent to use UserParameter which invokes bash script with zabbix_sender execution, default timeout option is OK.
4. On Server compile and start the following code snippet:

   #include <stdio.h>
   #include <netdb.h>
   #include <netinet/in.h>
   #include <stdlib.h>
   #include <string.h>
   #include <sys/socket.h>
   #include <sys/types.h>
   #define MAX 80
   #define PORT 8080
   #define SA struct sockaddr
   
   // Function designed for chat between client and server.
   void func(int sockfd)
   {
   	char buff[MAX];
   	int n;
   	// infinite loop for chat
   	for (;;) {
   		bzero(buff, MAX);
   
   		// read the message from client and copy it in buffer
   		read(sockfd, buff, sizeof(buff));
   		// print buffer which contains the client contents
   		printf("From client: %s\t To client : ", buff);
   		bzero(buff, MAX);
   		n = 0;
   		// copy server message in the buffer
   		while ((buff[n++] = getchar()) != '\n')
   			;
   
   		// and send that buffer to client
   		write(sockfd, buff, sizeof(buff));
   
   		// if msg contains "Exit" then server exit and chat ended.
   		if (strncmp("exit", buff, 4) == 0) {
   			printf("Server Exit...\n");
   			break;
   		}
   	}
   }
   
   // Driver function
   int main()
   {
   	int sockfd, connfd, len;
   	struct sockaddr_in servaddr, cli;
   
   	// socket create and verification
   	sockfd = socket(AF_INET, SOCK_STREAM, 0);
   	if (sockfd == -1) {
   		printf("socket creation failed...\n");
   		exit(0);
   	}
   	else
   		printf("Socket successfully created..\n");
   	bzero(&servaddr, sizeof(servaddr));
   
   	// assign IP, PORT
   	servaddr.sin_family = AF_INET;
   	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
   	servaddr.sin_port = htons(PORT);
   
   	// Binding newly created socket to given IP and verification
   	if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) {
   		printf("socket bind failed...\n");
   		exit(0);
   	}
   	else
   		printf("Socket successfully binded..\n");
   
   	// Now server is ready to listen and verification
   	if ((listen(sockfd, 5)) != 0) {
   		printf("Listen failed...\n");
   		exit(0);
   	}
   	else
   		printf("Server listening..\n");
   	len = sizeof(cli);
   
   	// Accept the data packet from client and verification
   	connfd = accept(sockfd, (SA*)&cli, &len);
   	if (connfd < 0) {
   		printf("server acccept failed...\n");
   		exit(0);
   	}
   	else
   		printf("server acccept the client...\n");
   
   	// Function for chatting between client and server
           sleep(600);
   	func(connfd);
   
   	// After chatting close the socket
   	close(sockfd);
   }
   

5. Using Zabbix get request UserParameter (on port 8080 for zabbix_sender inside script of the example of the fake server), check list of the semaphores:

   root@sol11:~# ipcs -a
   IPC status from <running system> as of Thursday, April 22, 2021 12:48:42 PM EEST
   T         ID      KEY        MODE        OWNER    GROUP  CREATOR   CGROUP CBYTES  QNUM QBYTES LSPID LRPID   STIME    RTIME    CTIME 
   Message Queues:
   T         ID      KEY        MODE        OWNER    GROUP  CREATOR   CGROUP NATTCH      SEGSZ   CPID  LPID   ATIME    DTIME    CTIME 
   Shared Memory:
   T         ID      KEY        MODE        OWNER    GROUP  CREATOR   CGROUP NSEMS   OTIME    CTIME 
   Semaphores:
   s          8   0x0        --ra-------   zabbix   zabbix   zabbix   zabbix    16 no-entry 12:48:36
   s          7   0x0        --ra-------   zabbix   zabbix   zabbix   zabbix    16 no-entry 12:48:16
   s          6   0x0        --ra-------   zabbix   zabbix   zabbix   zabbix    16 12:48:41 12:47:52
   

Expected:
No semaphores left.