Getting segfault after updating/adding around 2K routes

[lucch]

I'm trying to run the function below, which is similar to test_lookup_linx() in basic.c:

static int
test_load_random(void)
{
    struct poptrie *poptrie;
    int prefix[4];
    int prefixlen;
    int nexthop[4];
    int ret;
    u32 addr1;
    u32 addr2;

    srand(time(NULL));

    /* Initialize */
    poptrie = poptrie_init(NULL, 19, 22);
    if ( NULL == poptrie ) {
        return -1;
    }

    /* Load some random routes */
    for (size_t i = 0; i < 622607; i++) {
	prefix[0] = rand() % 256;
	prefix[1] = rand() % 256;
	prefix[2] = rand() % 256;
	prefix[3] = rand() % 256;
	prefixlen = rand() % 33;
	nexthop[0] = rand() % 256;
	nexthop[1] = rand() % 256;
	nexthop[2] = rand() % 256;
	nexthop[3] = rand() % 256;

        /* Convert to u32 */
        addr1 = ((u32)prefix[0] << 24) + ((u32)prefix[1] << 16)
            + ((u32)prefix[2] << 8) + (u32)prefix[3];
        addr2 = ((u32)nexthop[0] << 24) + ((u32)nexthop[1] << 16)
            + ((u32)nexthop[2] << 8) + (u32)nexthop[3];

        /* Add an entry */
        ret = poptrie_route_update(poptrie, addr1, prefixlen, (void *)(u64)addr2);
        if ( ret != 0 ) {
            return -1;
        }

        /* Test progress */
        printf(".");
        fflush(stdout);
    }

    /* Release */
    poptrie_release(poptrie);

    return 0;
}

int
main()
{
    test_load_random();

    return 0;
}

However, I'm getting segfaults after updating/adding some routes as below:

[alexandrelucchesi@phi poptrie]$ ./a.out | wc -m
2529
[alexandrelucchesi@phi poptrie]$ ./a.out | wc -m
2491
[alexandrelucchesi@phi poptrie]$ ./a.out | wc -m
2547
[alexandrelucchesi@phi poptrie]$ ./a.out | wc -m
2535
[alexandrelucchesi@phi poptrie]$ ./a.out | wc -m
2510

I've tried to compile the poptrie library and my code using both icc and gcc, but I've got the same results either way.

Could you please give some directions?

[ljluestc]

The segmentation fault (segfault) you're encountering in your code typically occurs due to memory access violations. In the code you provided, there is a potential issue that could lead to memory corruption or segmentation faults:

ret = poptrie_route_update(poptrie, addr1, prefixlen, (void *)(u64)addr2);

Here, you are casting addr2 to a void* and then back to u64. This type of casting can lead to undefined behavior and potential issues with memory access.

To resolve this issue, you should avoid unnecessary type casting. Here's an updated version of your code:

ret = poptrie_route_update(poptrie, addr1, prefixlen, (void*)(uintptr_t)addr2);

In this updated code, we cast addr2 to uintptr_t and then to void*. This is a safer way to perform the casting, and it should help prevent memory access violations.