Crash when creating and reading local variable concurrently #754

notramo · 2018-09-23T17:39:41Z

I added the following to my rc.elv (it uses fzf for directory history matching):

edit:location:matcher = [pattern]{ input = [];
  each [in]{ input = [ $@input $in ] };
  for i $input {
    print $i"\x00"
  }|
    output = [(fzf --read0 -f $pattern)];
  for i $input {
    has-value $output $i
  }
}

Crash happens randomly. Probably when multiple fzf instances are running (I have a slow CPU).
OS: Void Linux glibc, but it also happens on Arch Linux (both x86_64).
Version (on Void):

Version: 0.12-rc2-dirty
Go version: go1.10.3
GOROOT at build time: /usr/lib/go
GOPATH at build time: /home/user/.go/

Backtrace:

 ~ >>>                                                                                                                                                                    [ user ]
 LOCATION  ffffffatal error: concurrent map read and map write
(no result)
goroutine 44095 [running]:
runtime.throw(0x91f468, 0x21)
/usr/lib/go/src/runtime/panic.go:616 +0x81 fp=0xc4202fb990 sp=0xc4202fb970 pc=0x42b9c1
runtime.mapaccess2_faststr(0x8efb00, 0xc4205a8690, 0xc420250029, 0x1, 0xc4202fba70, 0x0)
/usr/lib/go/src/runtime/hashmap_fast.go:270 +0x461 fp=0xc4202fba00 sp=0xc4202fb990 pc=0x40cc41
github.com/elves/elvish/eval.(*Frame).resolveUnqualified(...)
/home/user/.go/src/github.com/elves/elvish/eval/resolve.go:139
github.com/elves/elvish/eval.(*Frame).ResolveVar(0xc42027ff20, 0xc420250029, 0x0, 0xc420250029, 0x1, 0x300000002, 0xc4201abb00)
/home/user/.go/src/github.com/elves/elvish/eval/resolve.go:80 +0x6e6 fp=0xc4202fbad8 sp=0xc4202fba00 pc=0x7a41d6
github.com/elves/elvish/eval.varOp.Invoke(0xc420250029, 0x0, 0xc420250029, 0x1, 0xc42027ff20, 0x4854d0, 0xc42017c7d0, 0x7abdca, 0xc4201e33c0, 0x412938)
/home/user/.go/src/github.com/elves/elvish/eval/compile_lvalue.go:144 +0x63 fp=0xc4202fbb50 sp=0xc4202fbad8 pc=0x78e493
github.com/elves/elvish/eval.(*varOp).Invoke(0xc420369a40, 0xc42027ff20, 0xc4201e34a8, 0x797b54, 0x855840, 0xc420580000, 0x1000)
<autogenerated>:1 +0x69 fp=0xc4202fbbb0 sp=0xc4202fbb50 pc=0x7b1a79
github.com/elves/elvish/eval.LValuesOp.Exec(0x971440, 0xc420369a40, 0x829, 0x82a, 0xc42027ff20, 0xc420580000, 0x1000, 0x1000, 0x7a5513, 0x971460)
/home/user/.go/src/github.com/elves/elvish/eval/compile_lvalue.go:30 +0x56 fp=0xc4202fbbf8 sp=0xc4202fbbb0 pc=0x78d626
github.com/elves/elvish/eval.(*forOp).Invoke(0xc42035bf00, 0xc42027ff20, 0xc4201e3500, 0x4ea1ac)
/home/user/.go/src/github.com/elves/elvish/eval/builtin_special.go:505 +0x6b fp=0xc4202fbcb8 sp=0xc4202fbbf8 pc=0x78a79b
github.com/elves/elvish/eval.(*formOp).Invoke(0xc420371790, 0xc42027ff20, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:322 +0xe00 fp=0xc4202fbe90 sp=0xc4202fbcb8 pc=0x7915d0
github.com/elves/elvish/eval.Op.Exec(0x9704a0, 0xc420371790, 0x825, 0x84a, 0xc42027ff20, 0x1000, 0x1000)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:30 +0x4d fp=0xc4202fbec0 sp=0xc4202fbe90 pc=0x78ee6d
github.com/elves/elvish/eval.(*Frame).Eval(0xc42027ff20, 0x9704a0, 0xc420371790, 0x825, 0x84a, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:129 +0xa2 fp=0xc4202fbf30 sp=0xc4202fbec0 pc=0x79e2b2
github.com/elves/elvish/eval.(*pipelineOp).Invoke.func1(0xc42027ff20, 0x9704a0, 0xc420371790, 0x825, 0x84a, 0xc42018d2b0, 0xc42023cf10, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:118 +0x60 fp=0xc4202fbfa0 sp=0xc4202fbf30 pc=0x7a8380
runtime.goexit()
/usr/lib/go/src/runtime/asm_amd64.s:2361 +0x1 fp=0xc4202fbfa8 sp=0xc4202fbfa0 pc=0x4593c1
created by github.com/elves/elvish/eval.(*pipelineOp).Invoke
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:117 +0x18d

goroutine 1 [semacquire]:
sync.runtime_Semacquire(0xc42023cf1c)
/usr/lib/go/src/runtime/sema.go:56 +0x39
sync.(*WaitGroup).Wait(0xc42023cf10)
/usr/lib/go/src/sync/waitgroup.go:129 +0x72
github.com/elves/elvish/eval.(*pipelineOp).Invoke(0xc420242ff0, 0xc4202f26c0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:155 +0x566
github.com/elves/elvish/eval.Op.Exec(0x970540, 0xc420242ff0, 0x825, 0x874, 0xc4202f26c0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:30 +0x4d
github.com/elves/elvish/eval.chunkOp.Invoke(0xc42035be80, 0x4, 0x4, 0xc4202f26c0, 0x1500000000000030, 0x8ecca0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:43 +0x81
github.com/elves/elvish/eval.Op.Exec(0x971240, 0xc4203843c0, 0x7ee, 0x8a4, 0xc4202f26c0, 0xc42031a020, 0xc42005ea08)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:30 +0x4d
github.com/elves/elvish/eval.(*Closure).Call(0xc42045bf40, 0xc4202f26c0, 0xc42044e110, 0x1, 0x1, 0xc4201701e0, 0x4120e9, 0xc4201a6420)
/home/user/.go/src/github.com/elves/elvish/eval/closure.go:130 +0x864
github.com/elves/elvish/eval.(*Frame).CaptureOutput.func1(0xc4202f26c0, 0x18, 0x1000000008c42c0)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:159 +0x5d
github.com/elves/elvish/eval.funcOp.Invoke(0xc420414280, 0xc4202f26c0, 0x10, 0xc42005ed28)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:574 +0x30
github.com/elves/elvish/eval.Op.Exec(0x971320, 0xc420414280, 0xffffffffffffffff, 0xffffffffffffffff, 0xc4202f26c0, 0x434e24, 0xc42005ed58)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:30 +0x4d
github.com/elves/elvish/eval.(*Frame).Eval(0xc4202f26c0, 0x971320, 0xc420414280, 0xffffffffffffffff, 0xffffffffffffffff, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:129 +0xa2
github.com/elves/elvish/eval.pcaptureOutputInner(0xc42005f038, 0x971320, 0xc420414280, 0xffffffffffffffff, 0xffffffffffffffff, 0xc420340660, 0xc420340680, 0x412938, 0x40)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:373 +0x29b
github.com/elves/elvish/eval.pcaptureOutput(0xc42005f038, 0x971320, 0xc420414280, 0xffffffffffffffff, 0xffffffffffffffff, 0x4100aa, 0x10, 0x8512e0, 0x8ecc01, 0xc42044e120)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:342 +0x168
github.com/elves/elvish/eval.(*Frame).CaptureOutput(0xc42005f038, 0x7f8269cf30a0, 0xc42045bf40, 0xc42044e110, 0x1, 0x1, 0xc4201701e0, 0x0, 0x6, 0xc42060fe10, ...)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:161 +0xd8
github.com/elves/elvish/edit/location.(*provider).Filter(0xc4202f23c0, 0xc42060fe10, 0x6, 0x0)
/home/user/.go/src/github.com/elves/elvish/edit/location/location.go:280 +0x433
github.com/elves/elvish/edit/edcore.(*listingState).refresh(0xc42007a190)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/listing.go:263 +0x46
github.com/elves/elvish/edit/edcore.(*listingState).changeFilter(0xc42007a190, 0xc42060fe10, 0x6)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/listing.go:259 +0x4b
github.com/elves/elvish/edit/edcore.(*listingState).defaultBinding(0xc42007a190, 0xc4201c2000)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/listing.go:337 +0xd8
github.com/elves/elvish/edit/edcore.initListing.func10()
/home/user/.go/src/github.com/elves/elvish/edit/edcore/listing.go:54 +0x39
reflect.Value.call(0x84a320, 0xc42015e560, 0x13, 0x90d134, 0x4, 0x0, 0x0, 0x0, 0x1d, 0x84a320, ...)
/usr/lib/go/src/reflect/value.go:447 +0x969
reflect.Value.Call(0x84a320, 0xc42015e560, 0x13, 0x0, 0x0, 0x0, 0x7b8d8d, 0xc42000e020, 0xc4204722c0)
/usr/lib/go/src/reflect/value.go:308 +0xa4
github.com/elves/elvish/eval.(*BuiltinFn).Call(0xc42015af00, 0xc4202f2600, 0x0, 0x0, 0x0, 0xc4201701e0, 0x8ecca0, 0xc42005f6f8)
/home/user/.go/src/github.com/elves/elvish/eval/builtin_fn.go:184 +0x55c
github.com/elves/elvish/eval.(*Frame).Call(0xc4202f2600, 0x970380, 0xc42015af00, 0x0, 0x0, 0x0, 0xc4201701e0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:143 +0xbb
github.com/elves/elvish/edit/edcore.(*editor).CallFn(0xc4201c2000, 0x970380, 0xc42015af00, 0x0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/api.go:115 +0x257
github.com/elves/elvish/edit/edcore.(*editor).ReadLine(0xc4201c2000, 0x0, 0x0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/edit.go:496 +0x9e0
github.com/elves/elvish/program/shell.interact.func1(0x895c00, 0xc42031fbc0, 0x13, 0x0)
/home/user/.go/src/github.com/elves/elvish/program/shell/interact.go:41 +0x2f
github.com/elves/elvish/program/shell.interact(0xc4200c70e0, 0xc4200223c0, 0x13, 0x0)
/home/user/.go/src/github.com/elves/elvish/program/shell/interact.go:51 +0x219
github.com/elves/elvish/program/shell.(*Shell).Main(0xc42018e440, 0xc42001e1a0, 0x0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/program/shell/shell.go:48 +0x1a7
github.com/elves/elvish/program.Main(0xc42001e1a0, 0x1, 0x1, 0x0)
/home/user/.go/src/github.com/elves/elvish/program/program.go:119 +0x180
main.main()
/home/user/.go/src/github.com/elves/elvish/main.go:14 +0x45

goroutine 5 [syscall]:
os/signal.signal_recv(0x973ee0)
/usr/lib/go/src/runtime/sigqueue.go:139 +0xa6
os/signal.loop()
/usr/lib/go/src/os/signal/signal_unix.go:22 +0x22
created by os/signal.init.0
/usr/lib/go/src/os/signal/signal_unix.go:28 +0x41

goroutine 7 [chan receive]:
github.com/elves/elvish/eval.init.13.func1()
/home/user/.go/src/github.com/elves/elvish/eval/port.go:49 +0x53
created by github.com/elves/elvish/eval.init.13
/home/user/.go/src/github.com/elves/elvish/eval/port.go:48 +0x49

goroutine 8 [IO wait]:
internal/poll.runtime_pollWait(0x7f8269ceef00, 0x72, 0xc420063ab8)
/usr/lib/go/src/runtime/netpoll.go:173 +0x57
internal/poll.(*pollDesc).wait(0xc42016e218, 0x72, 0xffffffffffffff00, 0x971c20, 0xb8d6e8)
/usr/lib/go/src/internal/poll/fd_poll_runtime.go:85 +0x9b
internal/poll.(*pollDesc).waitRead(0xc42016e218, 0xc420193000, 0x1000, 0x1000)
/usr/lib/go/src/internal/poll/fd_poll_runtime.go:90 +0x3d
internal/poll.(*FD).Read(0xc42016e200, 0xc420193000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/internal/poll/fd_unix.go:157 +0x17d
net.(*netFD).Read(0xc42016e200, 0xc420193000, 0x1000, 0x1000, 0xc4205661a0, 0x197, 0xc420566e80)
/usr/lib/go/src/net/fd_unix.go:202 +0x4f
net.(*conn).Read(0xc42000e598, 0xc420193000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/net/net.go:176 +0x6a
bufio.(*Reader).Read(0xc420094240, 0xc420025071, 0x1, 0x9, 0xc420063c98, 0x10, 0xc420001e00)
/usr/lib/go/src/bufio/bufio.go:216 +0x238
io.ReadAtLeast(0x96ffe0, 0xc420094240, 0xc420025071, 0x1, 0x9, 0x1, 0xc420063d10, 0x42add4, 0x9351e8)
/usr/lib/go/src/io/io.go:309 +0x86
io.ReadFull(0x96ffe0, 0xc420094240, 0xc420025071, 0x1, 0x9, 0xc420063d48, 0x405ac5, 0x42d79b)
/usr/lib/go/src/io/io.go:327 +0x58
encoding/gob.decodeUintReader(0x96ffe0, 0xc420094240, 0xc420025071, 0x9, 0x9, 0xc42007a020, 0xc420063e08, 0xc420063db8, 0x42a4d9)
/usr/lib/go/src/encoding/gob/decode.go:120 +0x63
encoding/gob.(*Decoder).recvMessage(0xc42016e400, 0xc420063dd0)
/usr/lib/go/src/encoding/gob/decoder.go:80 +0x57
encoding/gob.(*Decoder).decodeTypeSequence(0xc42016e400, 0x936800, 0xc42016e400)
/usr/lib/go/src/encoding/gob/decoder.go:142 +0x136
encoding/gob.(*Decoder).DecodeValue(0xc42016e400, 0x83f2e0, 0xc4201523f0, 0x16, 0x0, 0x0)
/usr/lib/go/src/encoding/gob/decoder.go:210 +0xdc
encoding/gob.(*Decoder).Decode(0xc42016e400, 0x83f2e0, 0xc4201523f0, 0x0, 0x0)
/usr/lib/go/src/encoding/gob/decoder.go:187 +0x14f
net/rpc.(*gobClientCodec).ReadResponseHeader(0xc420170900, 0xc4201523f0, 0xc4205661a0, 0x0)
/usr/lib/go/src/net/rpc/client.go:223 +0x45
net/rpc.(*Client).input(0xc420094300)
/usr/lib/go/src/net/rpc/client.go:109 +0xa7
created by net/rpc.NewClientWithCodec
/usr/lib/go/src/net/rpc/client.go:201 +0x92

goroutine 18 [select, locked to thread]:
runtime.gopark(0x936768, 0x0, 0x90f0f0, 0x6, 0x18, 0x1)
/usr/lib/go/src/runtime/proc.go:291 +0x11a
runtime.selectgo(0xc420042f50, 0xc4201a60c0)
/usr/lib/go/src/runtime/select.go:392 +0xe50
runtime.ensureSigM.func1()
/usr/lib/go/src/runtime/signal_unix.go:549 +0x1f4
runtime.goexit()
/usr/lib/go/src/runtime/asm_amd64.s:2361 +0x1

goroutine 19 [chan receive]:
github.com/elves/elvish/program/shell.handleSignals.func1(0xc4201a6000)
/home/user/.go/src/github.com/elves/elvish/program/shell/shell.go:70 +0xb8
created by github.com/elves/elvish/program/shell.handleSignals
/home/user/.go/src/github.com/elves/elvish/program/shell/shell.go:69 +0x7c

goroutine 20 [IO wait]:
internal/poll.runtime_pollWait(0x7f8269ceec90, 0x72, 0xc420053bc0)
/usr/lib/go/src/runtime/netpoll.go:173 +0x57
internal/poll.(*pollDesc).wait(0xc42015a338, 0x72, 0xffffffffffffff01, 0x971c20, 0xb8d6e8)
/usr/lib/go/src/internal/poll/fd_poll_runtime.go:85 +0x9b
internal/poll.(*pollDesc).waitRead(0xc42015a338, 0xc4201d2001, 0x1000, 0x1000)
/usr/lib/go/src/internal/poll/fd_poll_runtime.go:90 +0x3d
internal/poll.(*FD).Read(0xc42015a320, 0xc4201d2000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/internal/poll/fd_unix.go:157 +0x17d
os.(*File).read(0xc42015c168, 0xc4201d2000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/os/file_unix.go:226 +0x4e
os.(*File).Read(0xc42015c168, 0xc4201d2000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/os/file.go:107 +0x6a
bufio.(*Reader).fill(0xc420053f60)
/usr/lib/go/src/bufio/bufio.go:100 +0x11e
bufio.(*Reader).ReadSlice(0xc420053f60, 0x411c0a, 0x7f8269cf0498, 0x0, 0x0, 0x0, 0x57)
/usr/lib/go/src/bufio/bufio.go:341 +0x2c
bufio.(*Reader).ReadBytes(0xc420053f60, 0xa, 0x0, 0xc42003ce88, 0x442707, 0x1000, 0x8515a0)
/usr/lib/go/src/bufio/bufio.go:419 +0x6b
bufio.(*Reader).ReadString(0xc42003cf60, 0x100a, 0x1000, 0xc4201d2000, 0x1000, 0x1000)
/usr/lib/go/src/bufio/bufio.go:459 +0x38
github.com/elves/elvish/edit/edcore.NewEditor.func1(0xc42015c168, 0xc4201c2000, 0xc420156360)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/edit.go:120 +0x1cc
created by github.com/elves/elvish/edit/edcore.NewEditor
/home/user/.go/src/github.com/elves/elvish/edit/edcore/edit.go:117 +0x2bb

goroutine 21 [chan receive]:
github.com/elves/elvish/edit/edcore.NewEditor.func2(0xc4201a6300, 0xc4201c2000)
/home/user/.go/src/github.com/elves/elvish/edit/edcore/edit.go:132 +0xfe
created by github.com/elves/elvish/edit/edcore.NewEditor
/home/user/.go/src/github.com/elves/elvish/edit/edcore/edit.go:131 +0x2ea

goroutine 9 [chan receive]:
github.com/elves/elvish/edit/prompt.(*prompt).loop(0xc42016e480)
/home/user/.go/src/github.com/elves/elvish/edit/prompt/prompt.go:76 +0xd1
created by github.com/elves/elvish/edit/prompt.makePrompt
/home/user/.go/src/github.com/elves/elvish/edit/prompt/prompt.go:69 +0x1b4

goroutine 10 [chan receive]:
github.com/elves/elvish/edit/prompt.(*prompt).loop(0xc42016e500)
/home/user/.go/src/github.com/elves/elvish/edit/prompt/prompt.go:76 +0xd1
created by github.com/elves/elvish/edit/prompt.makePrompt
/home/user/.go/src/github.com/elves/elvish/edit/prompt/prompt.go:69 +0x1b4

goroutine 931 [runnable]:
syscall.Syscall6(0x10e, 0x7, 0xc42008a300, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0)
/usr/lib/go/src/syscall/asm_linux_amd64.s:44 +0x5
github.com/elves/elvish/vendor/golang.org/x/sys/unix.Pselect(0x7, 0xc42008a300, 0x0, 0x0, 0x0, 0x0, 0xc42015a280, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/vendor/golang.org/x/sys/unix/zsyscall_linux_amd64.go:1039 +0xc2
github.com/elves/elvish/sys.Select(0x7, 0xc42008a300, 0x0, 0x0, 0xc4201e06a7, 0x1)
/home/user/.go/src/github.com/elves/elvish/sys/select_linux.go:11 +0x51
github.com/elves/elvish/sys.WaitForRead(0xc4201e06e8, 0x2, 0x2, 0x0, 0x1, 0x0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/sys/waitforread_unix.go:23 +0x104
github.com/elves/elvish/edit/tty.(*runeReader).run(0xc420158480)
/home/user/.go/src/github.com/elves/elvish/edit/tty/rune_reader_unix.go:67 +0x84
created by github.com/elves/elvish/edit/tty.(*runeReader).Start
/home/user/.go/src/github.com/elves/elvish/edit/tty/rune_reader_unix.go:58 +0x3f

goroutine 932 [select]:
github.com/elves/elvish/edit/tty.(*reader).send(0xc420152750, 0x971120, 0xc42060fe78)
/home/user/.go/src/github.com/elves/elvish/edit/tty/reader_unix.go:100 +0xed
github.com/elves/elvish/edit/tty.(*reader).run(0xc420152750)
/home/user/.go/src/github.com/elves/elvish/edit/tty/reader_unix.go:72 +0x35f
created by github.com/elves/elvish/edit/tty.(*reader).Start
/home/user/.go/src/github.com/elves/elvish/edit/tty/reader_unix.go:58 +0xbb

goroutine 44011 [chan receive]:
github.com/elves/elvish/eval.pcaptureOutput.func1(0xc4202f2720)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:317 +0x66
github.com/elves/elvish/eval.pcaptureOutputInner.func1(0xc420340660, 0xc4202f2720, 0xc4201a6420)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:364 +0x30
created by github.com/elves/elvish/eval.pcaptureOutputInner
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:363 +0x220

goroutine 44012 [IO wait]:
internal/poll.runtime_pollWait(0x7f8269cee6e0, 0x72, 0xc420584b50)
/usr/lib/go/src/runtime/netpoll.go:173 +0x57
internal/poll.(*pollDesc).wait(0xc420204568, 0x72, 0xffffffffffffff01, 0x971c20, 0xb8d6e8)
/usr/lib/go/src/internal/poll/fd_poll_runtime.go:85 +0x9b
internal/poll.(*pollDesc).waitRead(0xc420204568, 0xc42068a001, 0x1000, 0x1000)
/usr/lib/go/src/internal/poll/fd_poll_runtime.go:90 +0x3d
internal/poll.(*FD).Read(0xc420204550, 0xc42068a000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/internal/poll/fd_unix.go:157 +0x17d
os.(*File).read(0xc4204b20c0, 0xc42068a000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/os/file_unix.go:226 +0x4e
os.(*File).Read(0xc4204b20c0, 0xc42068a000, 0x1000, 0x1000, 0x0, 0x0, 0x0)
/usr/lib/go/src/os/file.go:107 +0x6a
bufio.(*Reader).fill(0xc420584f38)
/usr/lib/go/src/bufio/bufio.go:100 +0x11e
bufio.(*Reader).ReadSlice(0xc420584f38, 0x411c0a, 0x7f8269d01fe8, 0x0, 0x0, 0x0, 0x57)
/usr/lib/go/src/bufio/bufio.go:341 +0x2c
bufio.(*Reader).ReadBytes(0xc420584f38, 0xa, 0x0, 0xc420719e18, 0x442707, 0x1000, 0x8515a0)
/usr/lib/go/src/bufio/bufio.go:419 +0x6b
bufio.(*Reader).ReadString(0xc420719f38, 0x100a, 0x1000, 0xc42068a000, 0x1000, 0x1000)
/usr/lib/go/src/bufio/bufio.go:459 +0x38
github.com/elves/elvish/eval.pcaptureOutput.func2(0xc4204b20c0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:326 +0x16c
github.com/elves/elvish/eval.pcaptureOutputInner.func2(0xc420340680, 0xc4204b20c0, 0xc4201a63c0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:368 +0x30
created by github.com/elves/elvish/eval.pcaptureOutputInner
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:367 +0x259

goroutine 44096 [runnable]:
github.com/elves/elvish/eval.(*Port).Fork(...)
/home/user/.go/src/github.com/elves/elvish/eval/port.go:17
github.com/elves/elvish/eval.(*Frame).fork(0xc42028e000, 0x915565, 0x10, 0xc420044800)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:115 +0xc3
github.com/elves/elvish/eval.pcaptureOutputInner(0xc42028e000, 0x971240, 0xc420369fa0, 0x85b, 0x872, 0xc420189060, 0xc420189080, 0xc4200652a0, 0x7b0038)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:348 +0x55
github.com/elves/elvish/eval.pcaptureOutput(0xc42028e000, 0x971240, 0xc420369fa0, 0x85b, 0x872, 0x0, 0x0, 0xc4200655b0, 0x78ce54, 0x971240)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:342 +0x168
github.com/elves/elvish/eval.outputCaptureOp.Invoke(0x971240, 0xc420369fa0, 0x85b, 0x872, 0xc42028e000, 0x2, 0x4120e9, 0xc42055c9c0, 0x60, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:310 +0x5a
github.com/elves/elvish/eval.ValuesOp.Exec(0x9713a0, 0xc420369fc0, 0x85a, 0x873, 0xc42028e000, 0xc42004f420, 0x411be5, 0x7f8269cfabd8, 0x3f, 0xc42004f440)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:35 +0x51
github.com/elves/elvish/eval.compoundOp.Invoke(0x0, 0xc420369e00, 0x1, 0x1, 0xc42028e000, 0x412938, 0x10, 0x855840, 0xc4203d2201, 0xc4204cc5a0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:71 +0x7f
github.com/elves/elvish/eval.ValuesOp.Exec(0x971260, 0xc420369fe0, 0x85a, 0x873, 0xc42028e000, 0xc42044e240, 0xc42060fe70, 0xc42004f710, 0x79db2c, 0x8512e0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:35 +0x51
github.com/elves/elvish/eval.listOp.Invoke(0xc420369de0, 0x1, 0x1, 0xc42028e000, 0x77fb07, 0xc4205a87b0, 0xc4205a87b0, 0xc42044e240, 0xc42060fe70)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:286 +0x10e
github.com/elves/elvish/eval.ValuesOp.Exec(0x971360, 0xc420384000, 0x859, 0x874, 0xc42028e000, 0x12, 0x86dc20, 0xc4205a8798, 0x86dc20, 0xc42044e230)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:35 +0x51
github.com/elves/elvish/eval.compoundOp.Invoke(0x7f8269d3a000, 0xc420369dc0, 0x1, 0x1, 0xc42028e000, 0x60, 0xc42004fa88, 0x442985, 0x413737, 0xc42018d2f0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:71 +0x7f
github.com/elves/elvish/eval.ValuesOp.Exec(0x971260, 0xc420384020, 0x859, 0x874, 0xc42028e000, 0x1, 0x1, 0x1, 0x0, 0x1)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:35 +0x51
github.com/elves/elvish/eval.(*compiler).form.func1(0xc42028e000, 0xc4201d79a0, 0x0, 0x8524e0, 0x1, 0xbea058)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:220 +0x12e
github.com/elves/elvish/eval.funcValuesOp.Invoke(0xc42036f030, 0xc42028e000, 0x42a4d9, 0xc4201d79d0, 0xc42004fbe0, 0x20, 0xc42004fbd8)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:573 +0x30
github.com/elves/elvish/eval.ValuesOp.Exec(0x971340, 0xc42036f030, 0xffffffffffffffff, 0xffffffffffffffff, 0xc42028e000, 0xc42004fc98, 0x0, 0x0, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_value.go:35 +0x51
github.com/elves/elvish/eval.(*assignmentOp).Invoke(0xc42037ade0, 0xc42028e000, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:411 +0x1f4
github.com/elves/elvish/eval.Op.Exec(0x970400, 0xc42037ade0, 0x850, 0xffffffffffffffff, 0xc42028e000, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:30 +0x4d
github.com/elves/elvish/eval.(*formOp).Invoke(0xc420371930, 0xc42028e000, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:362 +0xac1
github.com/elves/elvish/eval.Op.Exec(0x9704a0, 0xc420371930, 0x850, 0x874, 0xc42028e000, 0x1000, 0x1000)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:30 +0x4d
github.com/elves/elvish/eval.(*Frame).Eval(0xc42028e000, 0x9704a0, 0xc420371930, 0x850, 0x874, 0x0, 0x0)
/home/user/.go/src/github.com/elves/elvish/eval/frame.go:129 +0xa2
github.com/elves/elvish/eval.(*pipelineOp).Invoke.func1(0xc42028e000, 0x9704a0, 0xc420371930, 0x850, 0x874, 0xc42018d2b8, 0xc42023cf10, 0x1)
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:118 +0x60
created by github.com/elves/elvish/eval.(*pipelineOp).Invoke
/home/user/.go/src/github.com/elves/elvish/eval/compile_op.go:117 +0x18d

The text was updated successfully, but these errors were encountered:

xiaq · 2018-09-23T23:18:42Z

Aha, you found a concurrency bug.

This is happening because we use maps for scopes in Elvish, and since pipelines are executed in parallel, this line will both read and write to the scope:

for i $input { print $i"\x00" }| output = [(fzf --read0 -f $pattern)];

The read comes from $input while the write comes from the assignment to output.

I have failed to construct a smallest reproduction though. This code should trigger the same crash, but I haven't succeeded yet:

@a = (range 1000)
for _ $@ { } | @b = (all)

xiaq · 2018-09-23T23:25:44Z

Meanwhile, you can workaround the problem by moving the output construct up one level:

edit:location:matcher = [pattern]{
  input = []
  each [in]{ input = [ $@input $in ] }
  output = [(for i $input {
    print $i"\x00"
  }| fzf --read0 -f $pattern)]
  for i $input {
    has-value $output $i
  }
}

Also, you can use all to capture all inputs, and use @a = xxx to replace a = [xxx]:

edit:location:matcher = [pattern]{
  @input = (all)
  @output = (for i $input { print $i"\x00" }| fzf --read0 -f $pattern)
  for i $input {
    has-value $output $i
  }
}

The test now fails with "go test -race".

xiaq · 2020-01-14T13:14:38Z

I don't have a reproduction locally, but at least I have a test that now fails when run with go test -race.

xiaq · 2020-03-29T00:49:21Z

I believe this issue was fixed in 8c71635. Since I haven't been able to reproduce this locally and can't verify it, please reopen if this still reproduces.

xiaq changed the title ~~Crash in location mode~~ Crash when accessing the local scope concurrently in a pipeline Sep 23, 2018

xiaq added bug comp:lang labels Sep 24, 2018

xiaq added C:Race Condition and Panic and removed c:language labels Dec 28, 2019

xiaq added a commit that referenced this issue Jan 14, 2020

Add a test for #754.

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a3adcbf

The test now fails with "go test -race".

xiaq changed the title ~~Crash when accessing the local scope concurrently in a pipeline~~ Crash when creating and reading local variable concurrently Jan 14, 2020

krader1961 mentioned this issue Mar 25, 2020

Improve test coverage to at least 80% (measured by codecov) before releasing 0.14 #944

Closed

xiaq closed this Mar 29, 2020

elves / elvish

Crash when creating and reading local variable concurrently #754

Crash when creating and reading local variable concurrently #754

notramo commented Sep 23, 2018

xiaq commented Sep 23, 2018

xiaq commented Sep 23, 2018

xiaq commented Jan 14, 2020

xiaq commented Mar 29, 2020

elves / elvish

Crash when creating and reading local variable concurrently #754

Crash when creating and reading local variable concurrently #754

Comments

notramo commented Sep 23, 2018

xiaq commented Sep 23, 2018

xiaq commented Sep 23, 2018

xiaq commented Jan 14, 2020

xiaq commented Mar 29, 2020