Undefined

# Source

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

struct node {
    int something;
    struct node *next;
};


void free_circularly_linked_list(struct node *head) {
    struct node *tmp = head;
    do {
          struct node *next = tmp->next;
          free(tmp);
          tmp = next;
    } while (tmp != head);
}

int main() {
    struct node *somelist = malloc(sizeof(struct node));
    somelist->something = 7;
    somelist->next = malloc(sizeof(struct node));
    struct node *tmp = somelist->next;
    tmp->something = 9;
    tmp->next = somelist;


    printf("test\n");
    free_circularly_linked_list(somelist);
    return EXIT_SUCCESS;
}

# UBSan

$ clang -Wall -Wextra list.c -o list -fsanitize=undefined

$ ./list
test

# Clang's analyzer

$ scan-build clang -Wall -Wextra list.c -o list -fsanitize=undefined
scan-build: Using '/usr/bin/clang-3.8' for static analysis
scan-build: Removing directory '/tmp/scan-build-2016-05-19-065614-1236-1' because it contains no reports.
scan-build: No bugs found.

# Facebook - infer

# infer -- clang -c -Wall list.c
Starting analysis (Infer version v0.6.0)
Computing dependencies... 100%
Creating clusters... 100%
Analyzing 1 clusters.Analysis finished in 0.014290s
Analyzed 2 procedures in 1 file
No issues found

# tis-interpreter

# sh tis-interpreter.sh /code/list.c
[value] Analyzing a complete application starting at main
[value] Computing initial state
[value] Initial state computed

test

/code/list.c:16:[kernel] warning: accessing left-value that contains escaping addresses:
                  assert ¬\dangling(&head);
                  stack: free_circularly_linked_list :: /code/list.c:29 <- main
[value] Stopping at nth alarm
[value] user error: Degeneration occurred:
                    results are not correct for lines of code that can be reached from the degeneration point.