[Bug nptl/13690] pthread_mutex_unlock potentially cause invalid access

["triegel at redhat dot com" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=13690

Torvald Riegel <triegel at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
   Target Milestone|2.22                        |2.18

--- Comment #51 from Torvald Riegel <triegel at redhat dot com> ---
The spurious wake-up issue has been discussed with the Kernel community, and
the conclusion was to essentially document this behavior.  A current draft of
an updated futex manpage has the following wording:

       FUTEX_WAIT
              Returns 0 if the caller was woken up.  Note that a  wake-up  can
              also  be caused by common futex usage patterns in unrelated code
              that happened to have previously used the  futex  word's  memory
              location  (e.g., typical futex-based implementations of Pthreads
              mutexes can cause this under some conditions).  Therefore, call‐
              ers should always conservatively assume that a return value of 0
              can mean a spurious wake-up, and  use  the  futex  word's  value
              (i.e., the user space synchronization scheme)
                  to decide whether to continue to block or not.

I've send an updated patch for review:
https://sourceware.org/ml/libc-alpha/2015-07/msg00411.html
Compared to the patch posted here, it fixes the problem in __lll_unlock and
__lll_robust_unlock, and fixes a similar problem in
__pthread_mutex_unlock_full.

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Subject: [Bug ports/18674] New: trunk/sysdeps/i386/tst-auditmod3b.c:84: possible missing break ?
Date: Tue, 14 Jul 2015 20:38:00 -0000
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https://sourceware.org/bugzilla/show_bug.cgi?id\x18674

            Bug ID: 18674
           Summary: trunk/sysdeps/i386/tst-auditmod3b.c:84: possible
                    missing break ?
           Product: glibc
           Version: 2.21
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ports
          Assignee: unassigned at sourceware dot org
          Reporter: dcb314 at hotmail dot com
                CC: carlos at redhat dot com, roland at gnu dot org
  Target Milestone: ---

[trunk/sysdeps/i386/tst-auditmod3b.c:84] ->
[trunk/sysdeps/i386/tst-auditmod3b.c:86]: (warning) Variable 'flagstr' is
reassigned a value before the old one has been used. 'break;' missing?

Source code is

    case LA_SER_DEFAULT:
      flagstr = "LA_SER_DEFAULT";
    case LA_SER_SECURE:
      flagstr = "LA_SER_SECURE";
      break;

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