Suricata

scan-build-19 throws this warning:

datasets.c:187:12: warning: Call to blocking function 'fgets' inside of critical section [unix.BlockInCriticalSection]
  187 |     while (fgets(line, (int)sizeof(line), fp) != NULL) {
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
datasets.c:292:12: warning: Call to blocking function 'fgets' inside of critical section [unix.BlockInCriticalSection]
  292 |     while (fgets(line, (int)sizeof(line), fp) != NULL) {
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
datasets.c:368:12: warning: Call to blocking function 'fgets' inside of critical section [unix.BlockInCriticalSection]
  368 |     while (fgets(line, (int)sizeof(line), fp) != NULL) {
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
datasets.c:442:12: warning: Call to blocking function 'fgets' inside of critical section [unix.BlockInCriticalSection]
  442 |     while (fgets(line, (int)sizeof(line), fp) != NULL) {
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
datasets.c:512:12: warning: Call to blocking function 'fgets' inside of critical section [unix.BlockInCriticalSection]
  512 |     while (fgets(line, (int)sizeof(line), fp) != NULL) {
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5 warnings generated.

fgets also sees:

In file included from /usr/include/stdio.h:970,
                 from suricata-common.h:64,
                 from detect-engine-loader.c:24:
In function 'fgets',
    inlined from 'DetectLoadSigFile' at detect-engine-loader.c:134:11:
/usr/include/x86_64-linux-gnu/bits/stdio2.h:313:12: warning: argument 2 value -1 is negative [-Wstringop-overflow=]
  313 |     return __fgets_alias (__s, __n, __stream);
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/features.h:510,
                 from /usr/include/dirent.h:25,
                 from suricata-common.h:60:
/usr/include/x86_64-linux-gnu/bits/stdio2-decl.h: In function 'DetectLoadSigFile':
/usr/include/x86_64-linux-gnu/bits/stdio2-decl.h:96:14: note: in a call to function '__fgets_alias' declared with attribute 'access (write_only, 1, 2)'
   96 | extern char *__REDIRECT (__fgets_alias,
      |              ^~~~~~~~~~

Relevant doc: https://clang.llvm.org/docs/analyzer/checkers.html#unix-blockincriticalsection