[Bug nptl/19089] New: Robust mutexes do not take ROBUST_LIST_LIMIT into account

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=19089

            Bug ID: 19089
           Summary: Robust mutexes do not take ROBUST_LIST_LIMIT into
                    account
           Product: glibc
           Version: 2.23
            Status: NEW
          Severity: normal
          Priority: P2
         Component: nptl
          Assignee: unassigned at sourceware dot org
          Reporter: fweimer at redhat dot com
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---
             Flags: security-

Created attachment 8686
  --> https://sourceware.org/bugzilla/attachment.cgi?id=8686&action=edit
tst-robust10.c

The kernel limits the length of the robust mutex list to 2048 entries.  This
constant does not seem to be exported to user space.

glibc needs to keep track of the number of locked robust mutexes and fail
locking additional ones once ROBUST_LIST_LIMIT is exceeded.  Otherwise, some
locks will not be marked as EOWNERDEAD if the process exits while holding more
than ROBUST_LIST_LIMIT locks.

The attached test case fails if invoked with an argument of 2049.

I found this while looking for a cause for bug 19004, but I think this is a
completely different bug.

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