False Positive (doubleFree) after correcting common realloc error (memleakOnRealloc)

[Absinthe Sautereau]

This correctly generates [memleakOnRealloc]

int main (void) {
     char * x = malloc(100UL);
        x = realloc(x, 10000UL);
        ...

However, when corrected to this:

int main (void) {
  char * x = malloc(100UL);
  char * tmp = realloc(x, 10000UL);
  if (NULL == tmp) {
      free(x);
      return 1;
  } 
  x = tmp;
...

It incorrectly generates [doubleFree]

$ cppcheck --version
Cppcheck 1.89
$ uname -a
Linux qipk2dyy8 5.2.0-0.bpo.2-amd64 #1 SMP Debian 5.2.9-2~bpo10+1 (2019-08-25) x86_64 GNU/Linux

[Jean Pierre LeJacq]

I confirm the same with the latest production version:
$ cppcheck --version
Cppcheck 1.90
$ uname -a
Linux qipf14k7jn 5.4.0-0.bpo.2-amd64 #1 SMP Debian 5.4.8-1~bpo10+1 (2020-01-07) x86_64 GNU/Linux

[versat]

Thanks for reporting this issue.
It looks like there is already a ticket in the bug tracker: https://trac.cppcheck.net/ticket/9437 (FP: Double free on realloc check)