Wallet crashes repeatedly around voting time

[walkjivefly]

Multiple users have reported the wallet gets "crashy" around voting time. It seems to crash every time a stake is won. The behaviour persists from the first stake after voting in a superblock until some time after the relevant superblock.

If the stake involves servicenode collateral then the node also goes offline until the wallet is restarted and the node re-registered.

Wallets should not crash around voting time, or any other time, when a stake is won.

Not all users are affected. I personally have only been affected since adding some multisig addresses to my wallet. Others with similar wallets don't appear to be affected.

Blocknet Daemon version v4.3.3.0-8eef7c789

MX-Linux 19.x

There are no clues in the debug.log. I compiled a wallet with debug enabled and captured a core dump. The backtrace shows

Core was generated by `blocknetd'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  0x00005565269f3db3 in gov::RevoteOnStake (
    stakedHeight=@0x7f833a0f1990: 2329652, utxo=..., key=..., stakeUtxo=..., 
    wallet=wallet@entry=0x556564c7fd10, tx=..., params=...)
    at /home/mark/src/blocknet/depends/x86_64-pc-linux-gnu/share/../include/boost/variant/variant.hpp:2426
2426	    apply_visitor(Visitor& visitor)
[Current thread is 1 (Thread 0x7f833a0f2700 (LWP 31827))]
(gdb) bt
#0  0x00005565269f3db3 in gov::RevoteOnStake (
    stakedHeight=@0x7f833a0f1990: 2329652, utxo=..., key=..., stakeUtxo={...}, 
    wallet=wallet@entry=0x556564c7fd10, 
    tx=std::shared_ptr<const CTransaction> (empty) = {...}, params=...)
    at /home/mark/src/blocknet/depends/x86_64-pc-linux-gnu/share/../include/boost/variant/variant.hpp:2426
#1  0x0000556526a38b4a in BlockAssembler::CreateNewBlockPoS (
    this=this@entry=0x7f833a0f1920, stakeInput=..., stakeBlockHash=..., 
    stakeTime=@0x7f83f406cf10: 1642341470, 
    blockTime=@0x7f83f406cf18: 1642341456, keystore=<optimized out>, 
    disableValidationChecks=<optimized out>) at ./chainparams.h:60
#2  0x0000556526ae9ffc in StakeMgr::StakeBlock (this=<optimized out>, 
    stakeCoin=..., chainparams=...)
    at /usr/include/c++/8/bits/shared_ptr_base.h:1018
#3  0x0000556526aedf56 in StakeMgr::TryStake (this=0x7f83f4001400, 
    tip=<optimized out>, chainparams=...) at stakemgr.cpp:142
#4  0x0000556526af04f1 in ThreadStakeMinter ()
    at /usr/include/c++/8/bits/unique_ptr.h:342
#5  0x0000556526e3f8fb in thread_proxy ()
#6  0x00007f842d8bdfa3 in start_thread ()
   from /lib/x86_64-linux-gnu/libpthread.so.0
#7  0x00007f842d4bc4cf in clone () from /lib/x86_64-linux-gnu/libc.so.6

[walkjivefly]

Had a bunch more of these after voting in the last few days as SB approached. We should make this a high priority problem to fix when we manage to acquire a new C++ dev.

[walkjivefly]

Although these crashes are an effective way to disable a servicenode, they can happen regardless of whether the afflicted wallet has any servicenodes configured.

[ConanMishler]

I've noticed my staking wallet crashes consistently when the following two conditions are present:

1. My wallet is staking
2. I recently voted