[Bug sanitizer/88400] address-sanitizer on the cpu with only one core, may deadlock

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88400

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Please provide a testcase to reproduce the issue.  Also note that GCC 6 is no
longer supported.  This sounds like an issue in the libsanitizer interceptor
to me, the pthread_create interceptor does

    // Wait until the AsanThread object is initialized and the ThreadRegistry
    // entry is in "started" state. One reason for this is that after this
    // interceptor exits, the child thread's stack may be the only thing
holding
    // the |arg| pointer. This may cause LSan to report a leak if leak checking
    // happens at a point when the interceptor has already exited, but the
stack
    // range for the child thread is not yet known.
    while (atomic_load(&param.is_registered, memory_order_acquire) == 0)
      internal_sched_yield();

but sched_yield should allow other threads to do progress.  That might not
work if the current thread is realtime of course.  But isn't that a
user error (or a kernel bug when explicitely yield()ing)?