Re: [LTP] kill11: Skip with pipe-based core dump handlers

[linuxtestproject.agent@gmail.com]

Hi Jan,

On Wed, 08 Jul 2026 15:37:26 +0200, Jan Polensky wrote:
> kill11: Skip with pipe-based core dump handlers

> +	SAFE_FILE_SCANF("/proc/sys/kernel/core_pattern", "%255s", core_pattern);
> +	if (core_pattern[0] == '|') {
> +		tst_brk(TCONF,
> +			"Pipe-based core dumps detected (e.g., systemd-coredump). "
> +			"Test requires direct filesystem core dumps. "
> +			"Set kernel.core_pattern to a file path (e.g., /tmp/core.%%p) "
> +			"or disable systemd-coredump for proper testing.");
> +	}

The check is in setup(), which aborts all iterations when it triggers.
The hang described in the commit message can only occur when the child
receives a signal that actually generates a core dump -- i.e. the cases
with dumps_core == 1 (SIGQUIT, SIGILL, SIGABRT, SIGBUS, etc.).

For the 12+ cases with dumps_core == 0 (SIGHUP, SIGKILL, SIGTERM,
SIGPIPE, etc.) the child exits immediately without touching the core
dump path, so SAFE_WAIT() returns right away and the pipe handler is
never involved.

Placing the skip in setup() discards over half the test coverage on any
system running systemd-coredump, with no benefit for those cases.

Would it work to keep the core_pattern detection in setup() (store the
result in a static bool), then check it per-iteration in verify_kill()
only when tc->dumps_core is set?

  static bool pipe_based_coredump;

  static void setup(void)
  {
      char core_pattern[256];
      ...
      SAFE_FILE_SCANF("/proc/sys/kernel/core_pattern",
                      "%255s", core_pattern);
      pipe_based_coredump = (core_pattern[0] == '|');
  }

  static void verify_kill(unsigned int n)
  {
      struct tcase *tc = &tcases[n];

      if (tc->dumps_core && pipe_based_coredump) {
          tst_res(TCONF, "%s: pipe-based core dump handler active",
                  tst_strsig(tc->sig));
          return;
      }
      ...
  }

That way the non-core-dumping signal cases still run.

Verdict - Needs revision

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