Comment 35 for bug 1799497

Captured the hard lock on the following

(gdb) stepi
0xffffffff8c4e29e5 in ?? ()
=> 0xffffffff8c4e29e5: eb ec jmp 0xffffffff8c4e29d3
(gdb) stepi
0xffffffff8c4e29d3 in ?? ()
=> 0xffffffff8c4e29d3: 8b 07 mov (%rdi),%eax
(gdb) stepi
0xffffffff8c4e29d5 in ?? ()
=> 0xffffffff8c4e29d5: 85 c0 test %eax,%eax
(gdb) stepi
0xffffffff8c4e29d7 in ?? ()
=> 0xffffffff8c4e29d7: 75 0a jne 0xffffffff8c4e29e3
(gdb) stepi
0xffffffff8c4e29e3 in ?? ()
=> 0xffffffff8c4e29e3: f3 90 pause
(gdb) stepi
0xffffffff8c4e29e5 in ?? ()
=> 0xffffffff8c4e29e5: eb ec jmp 0xffffffff8c4e29d3

This maps to:

ffffffff810e29c0 <native_queued_spin_lock_slowpath>:
....
ffffffff810e29d3: 8b 07 mov (%rdi),%eax
ffffffff810e29d5: 85 c0 test %eax,%eax
ffffffff810e29d7: 75 0a jne ffffffff810e29e3 <native_queued_spin_lock_slowpath+0x23>
ffffffff810e29d9: f0 0f b1 17 lock cmpxchg %edx,(%rdi)
ffffffff810e29dd: 85 c0 test %eax,%eax
ffffffff810e29df: 75 f2 jne ffffffff810e29d3 <native_queued_spin_lock_slowpath+0x13>
ffffffff810e29e1: 5d pop %rbp
ffffffff810e29e2: c3 retq
ffffffff810e29e3: f3 90 pause
ffffffff810e29e5: eb ec jmp ffffffff810e29d3 <native_queued_spin_lock_slowpath+0x13>