Created attachment 1814520 [details]
reproducer

Description of problem:

I have a reproducer for an old and unrelated gcc bug. With glibc
2.34, the reproducer has started to behave differently than before
and it looks to me like a (glibc?) bug.

I'm attaching the program (rep.c) but the key functionality is:

  err = pthread_create(&th, NULL, tf, NULL);
  err = pthread_cancel(th);
  err = pthread_join(th, NULL);

repeated many times over.

Sometimes pthread_cancel returns ESRCH (this is what's actually
new, I haven't observed these failures before glibc 2.34 but
anyway). When pthread_cancel returns ESRCH then I'd expect the
subsequent pthread_join err with ESRCH, too. However it never
happens in the program.

To sum it up, pthread_cancel looks suspicious to me. It has
started to fail recently and the reported reason (ESRCH) doesn't
get "confirmed" by a subsequent pthread_join call.


Version-Release number of selected component (if applicable):

glibc-2.34-2.el9
gcc-11.2.1-2.2.el9
annobin-9.83-3.el9
kernel-5.14.0-0.rc4.35.el9


Steps to Reproduce:

1. gcc -O2 rep.c -g -o rep -lpthread
2. ./rep 200


Actual results:

Various numbers of the following line:
pthread_cancel failed: No thread with the ID thread could be found


Expected results:

I'd expect either
  * no pthread_cancel failures or
  * every pthread_cancel failure (err=ESRCH) be followed by
    a pthread_join failure (err=ESRCH).


Additional info:

* "Slow" machines tend to produce more occurrences of the problem.
* Not architecture specific