runtime/race: race programs episodically crash

[dvyukov]

This started around:
cmd/5g, cmd/5l, cmd/6g, cmd/6l, cmd/8g, cmd/8l, cmd/gc, runtime: generate pointer maps
by liveness analysis
and still happens. All crashes that I can find happen in the same place:

unexpected fault address 0x0
fatal error: fault
[signal 0xb code=0x80 addr=0x0 pc=0x455c15]
goroutine 36 [running]:
runtime.throw(0x8d9ff7)
    /usr/local/go/src/pkg/runtime/panic.c:462 +0x69 fp=0x7fc2819a77e0
runtime.sigpanic()
    /usr/local/go/src/pkg/runtime/os_linux.c:237 +0xe9 fp=0x7fc2819a77f8
database/sql.(*fakeDB).columnType(0xc21004e480, 0x603757, 0x2, 0x60375a, 0x4, ...)
    /usr/local/go/src/pkg/database/sql/fakedb_test.go:213 +0x175 fp=0x7fc2819a7880

http://build.golang.org/log/4a28a87adb2d49ce1aed0af7211820b6677afa71

[dvyukov]

Comment 1:

Here is another one I hit locally:
unexpected fault address 0x0
fatal error: fault
[signal 0xb code=0x80 addr=0x0 pc=0x49ff8b]
goroutine 7 [running]:
runtime.throw(0x9bb577)
    src/pkg/runtime/panic.c:462 +0x69 fp=0x7fae16f2b900
runtime.sigpanic()
    src/pkg/runtime/os_linux.c:237 +0xe9 fp=0x7fae16f2b918
unicode/utf8.DecodeLastRuneInString(0x636e75616c202f2f, 0x40, 0x425c92, 0x41b573)
    src/pkg/unicode/utf8/utf8.go:282 +0x6b fp=0x7fae16f2b960
strings.LastIndexAny(0x636e75616c202f2f, 0x40, 0x6897e0, 0x3, 0x7fae16f2b9e8)
    src/pkg/strings/strings.go:230 +0x89 fp=0x7fae16f2b9b8
go/doc.synopsisFmt(0x636e75616c202f2f, 0x40, 0x0, 0x0)
    src/pkg/go/doc/doc_test.go:51 +0x84 fp=0x7fae16f2ba08
runtime.call32(0x710610, 0xc21015bf60)
    src/pkg/runtime/asm_amd64.s:339 +0x32 fp=0x7fae16f2ba30
reflect.Value.call(0x620660, 0x710610, 0x0, 0x130, 0x685200, ...)
    src/pkg/reflect/value.go:614 +0x1801 fp=0x7fae16f2bf40
----- stack segment boundary -----
reflect.Value.Call(0x620660, 0x710610, 0x0, 0x130, 0xc21015bf40, ...)
    src/pkg/reflect/value.go:451 +0xb3 fp=0x7fae16f2c130
text/template.(*state).evalCall(0xc2101a4a80, 0x5e69a0, 0xc2101be6e8, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:555 +0xaaf fp=0x7fae16f2c3c0
text/template.(*state).evalFunction(0xc2101a4a80, 0x5e69a0, 0xc2101be6e8, 0x0, 0x166,
...)
    src/pkg/text/template/exec.go:447 +0x30e fp=0x7fae16f2c530
text/template.(*state).evalCommand(0xc2101a4a80, 0x5e69a0, 0xc2101be6e8, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:351 +0x226 fp=0x7fae16f2c678
text/template.(*state).evalPipeline(0xc2101a4a80, 0x5e69a0, 0xc2101be6e8, 0x0, 0x166,
...)
    src/pkg/text/template/exec.go:324 +0x1cc fp=0x7fae16f2c7f8
text/template.(*state).walk(0xc2101a4a80, 0x5e69a0, 0xc2101be6e8, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:159 +0x175 fp=0x7fae16f2c950
text/template.(*state).walk(0xc2101a4a80, 0x5e69a0, 0xc2101be6e8, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:167 +0x927 fp=0x7fae16f2caa8
text/template.func·001(0x5f8fa0, 0x0, 0x0, 0x20, 0x5e69a0, ...)
    src/pkg/text/template/exec.go:249 +0x447 fp=0x7fae16f2cbb8
text/template.(*state).walkRange(0xc2101a4a80, 0x5e6ac0, 0xc2101a4a48, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:258 +0x50e fp=0x7fae16f2cdb8
text/template.(*state).walk(0xc2101a4a80, 0x5e6ac0, 0xc2101a4a48, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:170 +0x2ed fp=0x7fae16f2cf10
text/template.(*state).walk(0xc2101a4a80, 0x5e6ac0, 0xc2101a4a48, 0x0, 0x166, ...)
    src/pkg/text/template/exec.go:167 +0x927 fp=0x7fae16f2d068
text/template.func·001(0x5f8fa0, 0x0, 0x1, 0x20, 0x5e6ac0, ...)
    src/pkg/text/template/exec.go:249 +0x447 fp=0x7fae16f2d178
text/template.(*state).walkRange(0xc2101a4a80, 0x5ed540, 0xc21014ccd8, 0x0, 0x176, ...)
    src/pkg/text/template/exec.go:258 +0x50e fp=0x7fae16f2d378
text/template.(*state).walk(0xc2101a4a80, 0x5ed540, 0xc21014ccd8, 0x0, 0x176, ...)
    src/pkg/text/template/exec.go:170 +0x2ed fp=0x7fae16f2d4d0
text/template.(*state).walk(0xc2101a4a80, 0x5ed540, 0xc21014ccd8, 0x0, 0x176, ...)
    src/pkg/text/template/exec.go:167 +0x927 fp=0x7fae16f2d628
text/template.(*state).walkIfOrWith(0xc2101a4a80, 0x13, 0x65da40, 0xc2101a2af0, 0x0, ...)
    src/pkg/text/template/exec.go:195 +0x277 fp=0x7fae16f2d708
text/template.(*state).walk(0xc2101a4a80, 0x65da40, 0xc2101a2af0, 0x0, 0x192, ...)
    src/pkg/text/template/exec.go:178 +0x796 fp=0x7fae16f2d860
text/template.(*state).walk(0xc2101a4a80, 0x65da40, 0xc2101a2af0, 0x0, 0x192, ...)
    src/pkg/text/template/exec.go:167 +0x927 fp=0x7fae16f2d9b8
text/template.(*Template).Execute(0xc21005c780, 0x7fae176da638, 0xc210176460, 0x65da40,
0xc2101a2af0, ...)
    src/pkg/text/template/exec.go:147 +0x504 fp=0x7fae16f2dbf0
go/doc.test(0xc2100703f0, 0x1)
    src/pkg/go/doc/doc_test.go:112 +0x7d1 fp=0x7fae16f2df28
go/doc.Test(0xc2100703f0)
    src/pkg/go/doc/doc_test.go:144 +0x55 fp=0x7fae16f2df40
testing.tRunner(0xc2100703f0, 0x9b9a48)
    src/pkg/testing/testing.go:391 +0x110 fp=0x7fae16f2df90
runtime.goexit()
    src/pkg/runtime/proc.c:1395 fp=0x7fae16f2df98
created by testing.RunTests
    src/pkg/testing/testing.go:471 +0xb98
goroutine 1 [chan receive]:
runtime.park(0x40adc0, 0xc2100a9110, 0x9bb30d)
    src/pkg/runtime/proc.c:1343 +0x66
runtime.chanrecv(0x5f0a20, 0xc2100a90c0, 0x7fae16f13cc0, 0x0, 0x0)
    src/pkg/runtime/chan.c:354 +0x56a
runtime.chanrecv1(0x5f0a20, 0xc2100a90c0, 0xc2100a90c0, 0x2)
    src/pkg/runtime/chan.c:446 +0x38
testing.RunTests(0x710650, 0x9b9a00, 0x6, 0x6, 0x426d01)
    src/pkg/testing/testing.go:472 +0xbe5
testing.Main(0x710650, 0x9b9a00, 0x6, 0x6, 0x9d0f20, ...)
    src/pkg/testing/testing.go:403 +0xae
main.main()
    /tmp/go-build496672830/go/doc/_test/_testmain.go:59 +0xdd
runtime.main()
    src/pkg/runtime/proc.c:221 +0x11f
runtime.goexit()
    src/pkg/runtime/proc.c:1395
goroutine 2 [syscall]:
runtime.notetsleepg(0x7fae16f31f60, 0xdf8475800)
    src/pkg/runtime/lock_futex.c:190 +0x46
runtime.MHeap_Scavenger()
    src/pkg/runtime/mheap.c:463 +0xa3
runtime.goexit()
    src/pkg/runtime/proc.c:1395
created by runtime.main
    src/pkg/runtime/proc.c:180
FAIL    go/doc  0.207s

[dvyukov]

Comment 2:

Status changed to Duplicate.

Merged into issue #6928.