[Bug libstdc++/112089] New: std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[Bug libstdc++/112089] New: std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[d at ilvokhin dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

            Bug ID: 112089
           Summary: std::shared_lock::unlock should throw
                    operation_not_permitted instead
                    resource_deadlock_would_occur
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: d at ilvokhin dot com
  Target Milestone: ---

Based on C++ standard wording, when we call unlock and don't own anything we
should throw operation_not_permitted. Sec 33.6.5.5.3 from here
(https://eel.is/c++draft/thread.lock.shared.locking#25.1):
> void unlock();
> <...>
> Error conditions:
> operation_not_permitted — if on entry owns is false.

But current implementation throws resource_deadlock_would_occur instead:
https://github.com/gcc-mirror/gcc/blob/458db9b6149b2e9bef94ab76909eb914ed9f675a/libstdc%2B%2B-v3/include/std/shared_mutex#L823

It doesn't change much, just a little inconsistency.

[Bug libstdc++/112089] std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-10-25
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |redi at gcc dot gnu.org

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Good catch, thanks! I think I probably just copy&pasted the throw from one of
the locking functions, which throw resource_deadlock_would_occur if _M_owns is
true, and forgot to change the error code.

[Bug libstdc++/112089] std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:0c305f3dec9a992dd775a3b9607b7b1e8c051859

commit r14-4960-g0c305f3dec9a992dd775a3b9607b7b1e8c051859
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Oct 26 16:51:30 2023 +0100

    libstdc++: Fix exception thrown by std::shared_lock::unlock() [PR112089]

    The incorrect errc constant here looks like a copy&paste error.

    libstdc++-v3/ChangeLog:

            PR libstdc++/112089
            * include/std/shared_mutex (shared_lock::unlock): Change errc
            constant to operation_not_permitted.
            * testsuite/30_threads/shared_lock/locking/112089.cc: New test.

[Bug libstdc++/112089] std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.5

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed on trunk so far.

[Bug libstdc++/112089] std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:e46a07b0e8a2bb074b491e0bb54a5cc8c8051341

commit r13-8012-ge46a07b0e8a2bb074b491e0bb54a5cc8c8051341
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Oct 26 16:51:30 2023 +0100

    libstdc++: Fix exception thrown by std::shared_lock::unlock() [PR112089]

    The incorrect errc constant here looks like a copy&paste error.

    libstdc++-v3/ChangeLog:

            PR libstdc++/112089
            * include/std/shared_mutex (shared_lock::unlock): Change errc
            constant to operation_not_permitted.
            * testsuite/30_threads/shared_lock/locking/112089.cc: New test.

    (cherry picked from commit 0c305f3dec9a992dd775a3b9607b7b1e8c051859)

[Bug libstdc++/112089] std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Jonathan Wakely
<redi@gcc.gnu.org>:

https://gcc.gnu.org/g:c285c1b9a940bde745f296e1bfc1a5cfddb63254

commit r12-10252-gc285c1b9a940bde745f296e1bfc1a5cfddb63254
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Oct 26 16:51:30 2023 +0100

    libstdc++: Fix exception thrown by std::shared_lock::unlock() [PR112089]

    The incorrect errc constant here looks like a copy&paste error.

    libstdc++-v3/ChangeLog:

            PR libstdc++/112089
            * include/std/shared_mutex (shared_lock::unlock): Change errc
            constant to operation_not_permitted.
            * testsuite/30_threads/shared_lock/locking/112089.cc: New test.

    (cherry picked from commit 0c305f3dec9a992dd775a3b9607b7b1e8c051859)

[Bug libstdc++/112089] std::shared_lock::unlock should throw operation_not_permitted instead resource_deadlock_would_occur

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112089

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Backported for 13.3 and 12.4