Re: [Libevent-users] [2.0.19-stable] Infinite loop

[sahil aggarwal <sahil.agg15@xxxxxxxxx>]

Was able to reproduce by running the program in GDB and adding the
breakpoints at event.c:2476 and continuing from there.

So the heap has same event at multiple positions which can cause the
event in heap to have min_heap_idx = -1. Here is the current heap

$66 = {
  p = 0x63b890,
  n = 19,
  a = 32
}

(gdb) p base->timeheap.p[0]
$46 = (struct event *) 0x6024c0
(gdb) p base->timeheap.p[1]
$47 = (struct event *) 0x605190
(gdb) p base->timeheap.p[2]
$48 = (struct event *) 0x604c90   [a]
(gdb) p base->timeheap.p[3]
$49 = (struct event *) 0x604790
(gdb) p base->timeheap.p[4]
$50 = (struct event *) 0x604290   [b]
(gdb) p base->timeheap.p[5]
$51 = (struct event *) 0x603d90   [y]
(gdb) p base->timeheap.p[6]
$52 = (struct event *) 0x603890   [z]
(gdb) p base->timeheap.p[7]
$53 = (struct event *) 0x602e90
(gdb) p base->timeheap.p[8]
$54 = (struct event *) 0x603390
(gdb) p base->timeheap.p[9]
$55 = (struct event *) 0x602990   [x]
(gdb) p base->timeheap.p[10]
$56 = (struct event *) 0x604290   [b]
(gdb) p base->timeheap.p[11]
$57 = (struct event *) 0x602990   [x]
(gdb) p base->timeheap.p[12]
$58 = (struct event *) 0x603d90   [y]
(gdb) p base->timeheap.p[13]
$59 = (struct event *) 0x604c90   [a]
(gdb) p base->timeheap.p[14]
$60 = (struct event *) 0x603890   [z]


Not sure what is causing this corrupted heap state.

#include <stdlib.h>
#include <stdio.h>

#include <evhttp.h>
#include <event2/event.h>
#include <event2/buffer.h>
#include <event2/http.h>
#include <string.h>

#define MAX_CONN 10


void http_req_done(struct evhttp_request *req, void *ctx) {
        printf("Done\n");
}

void http_req(struct event_base *base, struct evhttp_connection *evcon, char *uri, char *host, char *data, size_t bytes) {
        struct evhttp_request *req;
        struct evbuffer *output_buffer;

        req = evhttp_request_new(http_req_done, base);
        if(req == NULL) {
                printf("req creation failed\n");
                return;
        }

        evhttp_add_header(req->output_headers, "Host", host);
        evhttp_add_header(req->output_headers, "Connection", "close");

        char buf[16]={0};
        evbuffer_add(req->output_buffer, data, bytes);
        evutil_snprintf(buf, sizeof(buf)-1, "%lu", (unsigned long)bytes);
        evhttp_add_header(req->output_headers, "Content-Type", "application/json");
        evhttp_add_header(req->output_headers, "Accept", "application/json");
        evhttp_add_header(req->output_headers, "Content-Length", buf);

        int returnValue = evhttp_make_request(evcon, req, EVHTTP_REQ_POST , uri);
        if(returnValue != 0) {
                printf("req failed\n");
                return;
        }
}

int main() {
        struct event_base *base;
        base = event_base_new();

        struct evhttp_connection *evcon_pool[MAX_CONN];
        int i=0;
        while( i < MAX_CONN) {
                evcon_pool[i] = evhttp_connection_base_new(base, NULL, "1.1.1.1", 8888);
                if(evcon_pool[i] == NULL) {
                        printf("connection setup failed\n");
             	}
                evhttp_connection_set_retries(evcon_pool[i], 5);
                evhttp_connection_set_timeout(evcon_pool[i], 5);
		i++;
        }

        i=0;
	int j=0;
	while(j < 10) {
        	while( i < 100 ) {
                	char *data = "blah blah blah! more blah";
                	http_req(base, evcon_pool[i%MAX_CONN], "/test", "1.1.1.1", data,strlen(data));
			i++;
        	}
	        event_base_dispatch(base);
		j++;
		sleep(1);
	}
}