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Keep mempool consistent during block-reorgs

This fixes a subtle bug involving block re-orgs and non-standard transactions.

Start with a block containing a non-standard transaction, and
one or more transactions spending it in the memory pool.

Then re-org away from that block to another chain that does
not contain the non-standard transaction.

Result before this fix: the dependent transactions get stuck
in the mempool without their parent, putting the mempool
in an inconsistent state.

Tested with a new unit test.
tags/v0.15.1
Gavin Andresen 6 years ago
parent
commit
ad9e86dca1
No account linked to committer's email address
3 changed files with 117 additions and 0 deletions
  1. 1
    0
      src/Makefile.test.include
  2. 104
    0
      src/test/mempool_tests.cpp
  3. 12
    0
      src/txmempool.cpp

+ 1
- 0
src/Makefile.test.include View File

@@ -50,6 +50,7 @@ BITCOIN_TESTS =\
test/hash_tests.cpp \
test/key_tests.cpp \
test/main_tests.cpp \
test/mempool_tests.cpp \
test/miner_tests.cpp \
test/mruset_tests.cpp \
test/multisig_tests.cpp \

+ 104
- 0
src/test/mempool_tests.cpp View File

@@ -0,0 +1,104 @@
// Copyright (c) 2011-2014 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "main.h"
#include "txmempool.h"
#include "util.h"

#include "test/test_bitcoin.h"

#include <boost/test/unit_test.hpp>
#include <list>

BOOST_FIXTURE_TEST_SUITE(mempool_tests, TestingSetup)

BOOST_AUTO_TEST_CASE(MempoolRemoveTest)
{
// Test CTxMemPool::remove functionality

// Parent transaction with three children,
// and three grand-children:
CMutableTransaction txParent;
txParent.vin.resize(1);
txParent.vin[0].scriptSig = CScript() << OP_11;
txParent.vout.resize(3);
for (int i = 0; i < 3; i++)
{
txParent.vout[i].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
txParent.vout[i].nValue = 33000LL;
}
CMutableTransaction txChild[3];
for (int i = 0; i < 3; i++)
{
txChild[i].vin.resize(1);
txChild[i].vin[0].scriptSig = CScript() << OP_11;
txChild[i].vin[0].prevout.hash = txParent.GetHash();
txChild[i].vin[0].prevout.n = i;
txChild[i].vout.resize(1);
txChild[i].vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
txChild[i].vout[0].nValue = 11000LL;
}
CMutableTransaction txGrandChild[3];
for (int i = 0; i < 3; i++)
{
txGrandChild[i].vin.resize(1);
txGrandChild[i].vin[0].scriptSig = CScript() << OP_11;
txGrandChild[i].vin[0].prevout.hash = txChild[i].GetHash();
txGrandChild[i].vin[0].prevout.n = 0;
txGrandChild[i].vout.resize(1);
txGrandChild[i].vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
txGrandChild[i].vout[0].nValue = 11000LL;
}


CTxMemPool testPool(CFeeRate(0));
std::list<CTransaction> removed;

// Nothing in pool, remove should do nothing:
testPool.remove(txParent, removed, true);
BOOST_CHECK_EQUAL(removed.size(), 0);

// Just the parent:
testPool.addUnchecked(txParent.GetHash(), CTxMemPoolEntry(txParent, 0, 0, 0.0, 1));
testPool.remove(txParent, removed, true);
BOOST_CHECK_EQUAL(removed.size(), 1);
removed.clear();
// Parent, children, grandchildren:
testPool.addUnchecked(txParent.GetHash(), CTxMemPoolEntry(txParent, 0, 0, 0.0, 1));
for (int i = 0; i < 3; i++)
{
testPool.addUnchecked(txChild[i].GetHash(), CTxMemPoolEntry(txChild[i], 0, 0, 0.0, 1));
testPool.addUnchecked(txGrandChild[i].GetHash(), CTxMemPoolEntry(txGrandChild[i], 0, 0, 0.0, 1));
}
// Remove Child[0], GrandChild[0] should be removed:
testPool.remove(txChild[0], removed, true);
BOOST_CHECK_EQUAL(removed.size(), 2);
removed.clear();
// ... make sure grandchild and child are gone:
testPool.remove(txGrandChild[0], removed, true);
BOOST_CHECK_EQUAL(removed.size(), 0);
testPool.remove(txChild[0], removed, true);
BOOST_CHECK_EQUAL(removed.size(), 0);
// Remove parent, all children/grandchildren should go:
testPool.remove(txParent, removed, true);
BOOST_CHECK_EQUAL(removed.size(), 5);
BOOST_CHECK_EQUAL(testPool.size(), 0);
removed.clear();

// Add children and grandchildren, but NOT the parent (simulate the parent being in a block)
for (int i = 0; i < 3; i++)
{
testPool.addUnchecked(txChild[i].GetHash(), CTxMemPoolEntry(txChild[i], 0, 0, 0.0, 1));
testPool.addUnchecked(txGrandChild[i].GetHash(), CTxMemPoolEntry(txGrandChild[i], 0, 0, 0.0, 1));
}
// Now remove the parent, as might happen if a block-re-org occurs but the parent cannot be
// put into the mempool (maybe because it is non-standard):
testPool.remove(txParent, removed, true);
BOOST_CHECK_EQUAL(removed.size(), 6);
BOOST_CHECK_EQUAL(testPool.size(), 0);
removed.clear();
}

BOOST_AUTO_TEST_SUITE_END()

+ 12
- 0
src/txmempool.cpp View File

@@ -444,6 +444,18 @@ void CTxMemPool::remove(const CTransaction &origTx, std::list<CTransaction>& rem
LOCK(cs);
std::deque<uint256> txToRemove;
txToRemove.push_back(origTx.GetHash());
if (fRecursive && !mapTx.count(origTx.GetHash())) {
// If recursively removing but origTx isn't in the mempool
// be sure to remove any children that are in the pool. This can
// happen during chain re-orgs if origTx isn't re-accepted into
// the mempool for any reason.
for (unsigned int i = 0; i < origTx.vout.size(); i++) {
std::map<COutPoint, CInPoint>::iterator it = mapNextTx.find(COutPoint(origTx.GetHash(), i));
if (it == mapNextTx.end())
continue;
txToRemove.push_back(it->second.ptx->GetHash());
}
}
while (!txToRemove.empty())
{
uint256 hash = txToRemove.front();

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