Valgrind Invalid read of size

Question

First off, I have looked through other similar questions and they don't help me. I have the following Valgrind output:

My Code:

int f_gozlemZamaniFarki(long long t1,long long t2)
{
    char *time1 = (char*)calloc(12,sizeof(char));
    char *time2 = (char*)calloc(12,sizeof(char));

    *time1 = '\0';
    *time2 = '\0';

    sprintf(time1,"%lli",t1);
    sprintf(time2,"%lli",t2);

    int year,month,day,hour,minute,timeDif;
    int status = 0;

    struct tm tm1;
    struct tm tm2;

    time_t timeF = NULL;
    time_t timeS = NULL;

    if(sscanf(time1,"%4d%2d%2d%2d%2d",&year,&month,&day,&hour,&minute) != EOF)
    {
        tm1.tm_year = year - 1900;
        tm1.tm_mon = month;
        tm1.tm_mdmonth = day;
        tm1.tm_hour = hour;
        tm1.tm_min = minute;
        tm1.tm_sec = 0;
        timeF = mktime(&tm1);
    }

    if(sscanf(time2,"%4d%2d%2d%2d%2d",&year,&month,&day,&hour,&minute) != EOF)
    {
        tm2.tm_year = year - 1900;
        tm2.tm_mon = month;
        tm2.tm_mdmonth = day;
        tm2.tm_hour = hour;
        tm2.tm_min = minute;
        tm2.tm_sec = 0;
        timeS = mktime(&tm2);
    }

    timeDif = (timeF - timeS) / 60;

    if ((timeDif < 0) || (timeDif > 59))
    {
        status = 1;
    }

    free(time1);
    free(time2);

    return status;
}

valngrid output

==12726== Invalid read of size 1
==12726==  Address 0x1786dccc is 0 bytes after a block of size 12 alloc'd
==12726==    at 0x4C2AE45: calloc (vg_replace_malloc.c:711)
==12726==    by 0x405171: f_gozlemZamaniFarki (in /home/aws/bin/awsdDataWriter)
==12726== Conditional jump or move depends on uninitialised value(s)
==12726==  Uninitialised value was created by a stack allocation
==12726==    at 0x405150: f_gozlemZamaniFarki (in /home/aws/bin/awsdDataWriter)

All my variables are initialized (i hope), so I don't understand why Valgrind is yelling at me. Do you have a suggestion to make the code right and to make the mistake?

[Please see this discussion on why not to cast the return value of `malloc()` and family in `C`.](http://stackoverflow.com/q/605845/2173917). — Sourav Ghosh, Nov 25 '16 at 13:42
Not related to your problem: `*time1 = '\0'` is useless, as you `sprintf(time1,...)` right after. — Jabberwocky, Nov 25 '16 at 13:47
Try `char *time1 = (char*)calloc(12,sizeof(char));`-> `char *time1 = (char*)calloc(13,sizeof(char));` and tell us if the problem still occurs. — Jabberwocky, Nov 25 '16 at 13:51
Please compile your program with debugging options such that valgrind can tell you the line in which your allocation occurs. And, no, not all your variables are initialized, `tm1` and `tm2` aren't. — Jens Gustedt, Nov 25 '16 at 13:53
thank you Michael; //*time1 = '\0'; char *time1 = (char*)calloc(13,sizeof(char)); problem is solved. — hanifigoktas, Nov 25 '16 at 14:25

score 0 · Answer 1 · edited Nov 26 '16 at 11:48

0

I changed these lines, which solved my problem.

char *time1 = (char*)calloc(13,sizeof(char));
char *time1 = (char*)calloc(13,sizeof(char));

//*time1 = '\0';
//*time2 = '\0';

edited Nov 26 '16 at 11:48

Jongware

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answered Nov 26 '16 at 11:44

hanifigoktas

40
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Valgrind Invalid read of size

1 Answers1