jmx-dev RFR: 8366092: [GCC static analyzer] UnixOperatingSystem.c warning: use of uninitialized value 'systemTicks'

[Matthias Baesken]

When using gcc static analyzer (-fanalyzer) with gcc 13.2 the following issue is reported :

/jdk/src/jdk.management/linux/native/libmanagement_ext/UnixOperatingSystem.c: In function 'get_jvmticks':
/jdk/src/jdk.management/linux/native/libmanagement_ext/UnixOperatingSystem.c:208:24: warning: use of uninitialized value 'systemTicks' [CWE-457] [-Wanalyzer-use-of-uninitialized-value]
  208 | pticks->usedKernel = systemTicks;


vsscanf usually/normally reads the systemTicks info from /proc file system. see
https://github.com/openjdk/jdk/blob/45726a1f8b8f76586037867a32b82f8ab9b96937/src/jdk.management/linux/native/libmanagement_ext/UnixOperatingSystem.c#L163
but we never check that the *exact* number of params is read with vsscanf :
n = vsscanf(tmp, fmt, args);
So potentially we could get a non complete info without systemTicks and the call would still succeed.

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Commit messages:
 - JDK-8366092

Changes: https://git.openjdk.org/jdk/pull/26962/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26962&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8366092
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/26962.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26962/head:pull/26962

PR: https://git.openjdk.org/jdk/pull/26962