SUMMARY
After upgrade and reboot to 5.15.0, kwallet refuse to open and reports a crash on every attempt.

STEPS TO REPRODUCE
1. Upgrade to the newest version of Neon User Edition
2. Install libpam-kwallet5
3. Reboot + Login and found the previously working KWallet crash on open requests. 

OBSERVED RESULT
here's the terminal output of kwalletd5:
```
kwalletd5: Checking for pam module
kwalletd5: Got pam-login param
kwalletd5: Waiting for hash on 6-
kwalletd5: Hash or environment not received
kwalletd5: /workspace/build/src/runtime/kwalletd/kwalletd.cpp:595：int KWalletD::internalOpen(const QString&, const QString&, bool, WId, bool, const QString&): assert ‘b->cipherType() != KWallet::BACKEND_CIPHER_UNKNOWN’ failed.
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kwalletd5 path = /usr/bin pid = 25574
KCrash: Arguments: /usr/bin/kwalletd5 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0
[1]  + 25574 suspended (signal)  kwalletd5 --pam-login 6 3

```
The stacktrace:
```
Application: kwalletd5 (kwalletd5), signal: Aborted
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f096393a6c0 (LWP 11951))]

Thread 3 (Thread 0x7f0948da2700 (LWP 11953)):
#0  0x00007f095f3b6bf9 in __GI___poll (fds=0x7f094401ad60, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f095a8d6539 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f095a8d664c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f095ff1115b in QEventDispatcherGlib::processEvents (this=0x7f0944000b20, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#4  0x00007f095feb264a in QEventLoop::exec (this=this@entry=0x7f0948da1d70, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f095fcda41a in QThread::exec (this=<optimized out>) at thread/qthread.cpp:531
#6  0x00007f096037f015 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007f095fcdbbc2 in QThreadPrivate::start (arg=0x7f09605f6d80) at thread/qthread_unix.cpp:361
#8  0x00007f09625786db in start_thread (arg=0x7f0948da2700) at pthread_create.c:463
#9  0x00007f095f3c388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f0952852700 (LWP 11952)):
#0  0x00007f095f3b6bf9 in __GI___poll (fds=0x7f0952851cb8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f095d0b3747 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f095d0b536a in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f0955414d4a in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007f095fcdbbc2 in QThreadPrivate::start (arg=0x560dc781baa0) at thread/qthread_unix.cpp:361
#5  0x00007f09625786db in start_thread (arg=0x7f0952852700) at pthread_create.c:463
#6  0x00007f095f3c388f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f096393a6c0 (LWP 11951)):
[KCrash Handler]
#6  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
#7  0x00007f095f2e2801 in __GI_abort () at abort.c:79
#8  0x00007f095f2d239a in __assert_fail_base (fmt=0x7f096392876b "%s%s%s:%u\357\274\232%s%s\345\201\207\350\256\276 \342\200\230%s\342\200\231 \345\244\261\350\264\245\343\200\202\n%n", assertion=assertion@entry=0x560dc5feef78 "b->cipherType() != KWallet::BACKEND_CIPHER_UNKNOWN", file=file@entry=0x560dc5feef40 "/workspace/build/src/runtime/kwalletd/kwalletd.cpp", line=line@entry=595, function=function@entry=0x560dc5fef780 <KWalletD::internalOpen(QString const&, QString const&, bool, unsigned long long, bool, QString const&)::__PRETTY_FUNCTION__> "int KWalletD::internalOpen(const QString&, const QString&, bool, WId, bool, const QString&)") at assert.c:92
#9  0x00007f095f2d2412 in __GI___assert_fail (assertion=assertion@entry=0x560dc5feef78 "b->cipherType() != KWallet::BACKEND_CIPHER_UNKNOWN", file=file@entry=0x560dc5feef40 "/workspace/build/src/runtime/kwalletd/kwalletd.cpp", line=line@entry=595, function=function@entry=0x560dc5fef780 <KWalletD::internalOpen(QString const&, QString const&, bool, unsigned long long, bool, QString const&)::__PRETTY_FUNCTION__> "int KWalletD::internalOpen(const QString&, const QString&, bool, WId, bool, const QString&)") at assert.c:101
#10 0x0000560dc5fcd2bb in KWalletD::internalOpen (this=this@entry=0x7ffd8ae5b130, appid=..., wallet=..., isPath=isPath@entry=false, w=w@entry=117440518, modal=modal@entry=true, service=...) at ./src/runtime/kwalletd/kwalletd.cpp:595
#11 0x0000560dc5fcd5f6 in KWalletD::doTransactionOpen (this=this@entry=0x7ffd8ae5b130, appid=..., wallet=..., isPath=<optimized out>, wId=117440518, modal=<optimized out>, service=...) at ./src/runtime/kwalletd/kwalletd.cpp:557
#12 0x0000560dc5fce2ef in KWalletD::processTransactions (this=0x7ffd8ae5b130) at ./src/runtime/kwalletd/kwalletd.cpp:239
#13 0x0000560dc5fed16c in KWalletD::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=0x560dc786d0b0) at ./obj-x86_64-linux-gnu/src/runtime/kwalletd/kwalletd5_autogen/EWIEGA46WW/moc_kwalletd.cpp:390
#14 0x00007f095fee4992 in QObject::event (this=0x7ffd8ae5b130, e=<optimized out>) at kernel/qobject.cpp:1249
#15 0x00007f096167d83c in QApplicationPrivate::notify_helper (this=this@entry=0x560dc7815c30, receiver=receiver@entry=0x7ffd8ae5b130, e=e@entry=0x560dc78da5c0) at kernel/qapplication.cpp:3752
#16 0x00007f0961684dd0 in QApplication::notify (this=0x7ffd8ae5b060, receiver=0x7ffd8ae5b130, e=0x560dc78da5c0) at kernel/qapplication.cpp:3499
#17 0x00007f095feb4328 in QCoreApplication::notifyInternal2 (receiver=0x7ffd8ae5b130, event=0x560dc78da5c0) at kernel/qcoreapplication.cpp:1061
#18 0x00007f095feb44fe in QCoreApplication::sendEvent (receiver=<optimized out>, event=event@entry=0x560dc78da5c0) at kernel/qcoreapplication.cpp:1451
#19 0x00007f095feb6e87 in QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x560dc7815db0) at kernel/qcoreapplication.cpp:1800
#20 0x00007f095feb7428 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1654
#21 0x00007f095ff11b23 in postEventSourceDispatch (s=0x560dc78862d0) at kernel/qeventdispatcher_glib.cpp:276
#22 0x00007f095a8d6387 in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007f095a8d65c0 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#24 0x00007f095a8d664c in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#25 0x00007f095ff1113f in QEventDispatcherGlib::processEvents (this=0x560dc788edf0, flags=...) at kernel/qeventdispatcher_glib.cpp:422
#26 0x00007f095feb264a in QEventLoop::exec (this=this@entry=0x7ffd8ae5af80, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#27 0x00007f095febb800 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1364
#28 0x0000560dc5fc2d8f in main (argc=<optimized out>, argv=<optimized out>) at ./src/runtime/kwalletd/main.cpp:232
```

EXPECTED RESULT
Let KWallet subsystem work as before.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Neon User Edition
KDE Plasma Version: 5.15.0
KDE Frameworks Version: 5.15.0
Qt Version: 5