From 9ac8001c7dee221b9adefeedeb51bbcaef695f4b Mon Sep 17 00:00:00 2001 From: Roman Khimov Date: Wed, 4 Mar 2020 20:26:18 +0300 Subject: [PATCH] core: protect (*Blockchain).keyCache with a lock Avoid failures like this: fatal error: concurrent map writes goroutine 103 [running]: runtime.throw(0xca6fe3, 0x15) /usr/lib64/go/1.12/src/runtime/panic.go:617 +0x72 fp=0xc000687988 sp=0xc000687958 pc=0x42d8d2 runtime.mapassign(0xb9d4a0, 0xc0000b1f80, 0xc000687a6c, 0x13bd940) /usr/lib64/go/1.12/src/runtime/map.go:590 +0x5e3 fp=0xc000687a10 sp=0xc000687988 pc=0x40e2a3 github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).verifyHashAgainstScript(0xc0000f8000, 0x1300d1f5a3d348be, 0x78607089e4fe9fab, 0xc0a21e4f71, 0xc000d16070, 0x1e2b8881f8178e92, 0xd589cfa965287bb8, 0x24a4e4f292ebc797, 0xb90d3120d878e619, 0xc0001d01e0, ...) /home/rik/dev/neo-go/pkg/core/blockchain.go:1866 +0x371 fp=0xc000687ad8 sp=0xc000687a10 pc=0x984ed1 github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).verifyHeaderWitnesses(0xc0000f8000, 0xc000d16000, 0xc00042d950, 0x1, 0xc00008a6c0) /home/rik/dev/neo-go/pkg/core/blockchain.go:1914 +0x209 fp=0xc000687c90 sp=0xc000687ad8 pc=0x985999 github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).verifyHeader(0xc0000f8000, 0xc000d16000, 0xc00042d950, 0xf0ee0049d611101f, 0xf8967398a8f9351b) /home/rik/dev/neo-go/pkg/core/blockchain.go:1254 +0x235 fp=0xc000687d70 sp=0xc000687c90 pc=0x97e4e5 github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).addHeaders(0xc0000f8000, 0x1, 0xc000d12000, 0x7d0, 0x7d0, 0x0, 0x1) /home/rik/dev/neo-go/pkg/core/blockchain.go:369 +0x266 fp=0xc000687e68 sp=0xc000687d70 pc=0x973f46 github.com/nspcc-dev/neo-go/pkg/core.(*Blockchain).AddHeaders(0xc0000f8000, 0xc000d12000, 0x7d0, 0x7d0, 0x0, 0xc0003640c0) /home/rik/dev/neo-go/pkg/core/blockchain.go:338 +0x51 fp=0xc000687eb0 sp=0xc000687e68 pc=0x973cb1 github.com/nspcc-dev/neo-go/pkg/network.(*Server).handleHeadersCmd(0xc00022c140, 0xdd0ca0, 0xc000374000, 0xc00000c020) /home/rik/dev/neo-go/pkg/network/server.go:431 +0x74 fp=0xc000687fc0 sp=0xc000687eb0 pc=0x9ce5e4 runtime.goexit() /usr/lib64/go/1.12/src/runtime/asm_amd64.s:1337 +0x1 fp=0xc000687fc8 sp=0xc000687fc0 pc=0x45ca51 created by github.com/nspcc-dev/neo-go/pkg/network.(*Server).handleMessage /home/rik/dev/neo-go/pkg/network/server.go:705 +0xa4a ... --- pkg/core/blockchain.go | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/pkg/core/blockchain.go b/pkg/core/blockchain.go index d452bc8a3..d0d4d5574 100644 --- a/pkg/core/blockchain.go +++ b/pkg/core/blockchain.go @@ -110,6 +110,8 @@ type Blockchain struct { memPool mempool.Pool + // This lock protects concurrent access to keyCache. + keyCacheLock sync.RWMutex // cache for block verification keys. keyCache map[util.Uint160]map[string]*keys.PublicKey @@ -1846,8 +1848,12 @@ func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transa vm.SetCheckedHash(checkedHash.BytesBE()) vm.LoadScript(verification) vm.LoadScript(witness.InvocationScript) - if useKeys && bc.keyCache[hash] != nil { - vm.SetPublicKeys(bc.keyCache[hash]) + if useKeys { + bc.keyCacheLock.RLock() + if bc.keyCache[hash] != nil { + vm.SetPublicKeys(bc.keyCache[hash]) + } + bc.keyCacheLock.RUnlock() } err = vm.Run() if vm.HasFailed() { @@ -1862,8 +1868,15 @@ func (bc *Blockchain) verifyHashAgainstScript(hash util.Uint160, witness *transa if !res { return errors.Errorf("signature check failed") } - if useKeys && bc.keyCache[hash] == nil { - bc.keyCache[hash] = vm.GetPublicKeys() + if useKeys { + bc.keyCacheLock.RLock() + _, ok := bc.keyCache[hash] + bc.keyCacheLock.RUnlock() + if !ok { + bc.keyCacheLock.Lock() + bc.keyCache[hash] = vm.GetPublicKeys() + bc.keyCacheLock.Unlock() + } } } else { return errors.Errorf("no result returned from the script")