Bug 28268

Summary:	nptl: Handle robust PI mutexes for !__ASSUME_SET_ROBUST_LIST
Product:	glibc	Reporter:	Adhemerval Zanella <adhemerval.zanella>
Component:	nptl	Assignee:	Not yet assigned to anyone <unassigned>
Status:	NEW ---
Severity:	normal	CC:	drepper.fsp
Priority:	P2
Version:	2.35
Target Milestone:	---
Host:		Target:
Build:		Last reconfirmed:

Description Adhemerval Zanella 2021-08-26 12:02:47 UTC

The robust PI mutexes are signaled by setting the LSB bit to 1, so the code requires to take this consideration before access the __pthread_mutex_s. 
This a bug on only visible on a handful of architectures where 
__NR_set_robust_list is not support due the missing CONFIG_HAVE_FUTEX_CMPXCHG.