Bug 1946977

Created attachment 1769835 [details]
pthread-crash.c

Description of problem:

The attached program segfaults when it calls pthread_join
for the first time:

$ ./pthread-crash 
about to call pthread_join on threads[0] ...
thread 1: finished OK
thread 5: finished OK
thread 7: finished OK
thread 3: finished OK
thread 0: finished OK
thread 2: finished OK
thread 4: finished OK
thread 6: finished OK
Aborted (core dumped)

Unfortunately because of a bug in gdb I'm unable to get
a complete stack trace (bug 1946948).  However the partial
stack trace is:

Core was generated by `./pthread-crash'.
Program terminated with signal SIGABRT, Aborted.
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
50	  return ret;
[Current thread is 1 (Thread 0xffffb378f1e0 (LWP 440499))]
(gdb) bt
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1  0x0000ffffb3fc096c in __GI_abort () at abort.c:79
#2  0x0000ffffafeed594 in uw_update_context_1 (
    context=context@entry=0xffffb378e180, fs=fs@entry=0xffffb378d670)
    at ../../../libgcc/unwind-dw2.c:1442
#3  0x0000ffffafeed8e0 in uw_update_context (
    context=context@entry=0xffffb378e180, fs=fs@entry=0xffffb378d670)
    at ../../../libgcc/unwind-dw2.c:1518
#4  0x0000ffffafeedaf4 in uw_advance_context (fs=0xffffb378d670, 
    context=0xffffb378e180) at ../../../libgcc/unwind-dw2.c:1546
#5  _Unwind_ForcedUnwind_Phase2 (exc=exc@entry=0xffffb378f650, 
    context=context@entry=0xffffb378e180, 
    frames_p=frames_p@entry=0xffffb378ddb8) at ../../../libgcc/unwind.inc:192
#6  0x0000ffffafeedeb8 in _Unwind_ForcedUnwind (exc=0xffffb378f650, 
    stop=stop@entry=0xffffb4130ca0 <unwind_stop>, stop_argument=0xffffb378ea00)
    at ../../../libgcc/unwind.inc:217
#7  0x0000ffffb4130e30 in __GI___pthread_unwind (buf=<optimized out>)
    at unwind.c:121
#8  0x0000ffffb41287e8 in __do_cancel () at pthreadP.h:304
#9  __pthread_exit (
../../gdb/dwarf2-frame.c:1061: internal-error: Unknown CFA rule.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) 

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

glibc-2.28-154.el8.aarch64

How reproducible:

100%

Steps to Reproduce:
1. Compile and run the attached program.