perf machine: Fix NULL parent dereference in fork event processing

machine__process_fork_event() calls machine__findnew_thread() for the
parent thread, which can return NULL on allocation failure.  The code
then dereferences parent via thread__pid(parent) without a NULL check
when validating whether the parent PID matches.  The later NULL check
at thread__fork() does not prevent this earlier dereference.

Add a NULL guard before accessing the parent thread.

Fixes: 5cb73340d92a ("perf tools: Make fork event processing more resilient")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

0 files changed, 0 insertions, 0 deletions