runtime: panic in munmap

[SergeyTsalkov]

Using go 1.5.1, I got this crash in a process that allocates many GB of RAM in several maps. Probably a duplicate of #13227 but I'll let you guys decide that! It's repeatable, but involves an enormous and confidential data set.

$ go env
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/sergey/go"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GO15VENDOREXPERIMENT="1"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"

fatal error: unexpected signal during runtime execution
[signal 0xb code=0x1 addr=0xf1 pc=0x45f51b]

runtime stack:
runtime.throw(0xb744a0, 0x2a)
  /usr/local/go/src/runtime/panic.go:527 +0x90 fp=0x7f9a052d0d70 sp=0x7f9a052d0d58
runtime.sigpanic()
  /usr/local/go/src/runtime/sigpanic_unix.go:12 +0x5a fp=0x7f9a052d0dc0 sp=0x7f9a052d0d70
runtime.munmap(0x7f99eb1b1000, 0xb7ed28, 0x41c85f, 0x7f99eb1b1000, 0xb7ed28, 0xe00f60, 0x7f99eb1b1000, 0x16fda5, 0x1853d3, 0x41c07c, ...)
  /usr/local/go/src/runtime/sys_linux_amd64.s:266 +0x1b fp=0x7f9a052d0dc8 sp=0x7f9a052d0dc0
runtime.sysFree(0x7f99eb1b1000, 0xb7ed28, 0xe00f60)
  /usr/local/go/src/runtime/mem_linux.go:103 +0x34 fp=0x7f9a052d0de0 sp=0x7f9a052d0dc8
runtime.gcCopySpans()
  /usr/local/go/src/runtime/mgc.go:1600 +0xdf fp=0x7f9a052d0e18 sp=0x7f9a052d0de0
runtime.gcMark(0xbe16c05dffa)
  /usr/local/go/src/runtime/mgc.go:1415 +0x5c fp=0x7f9a052d0e80 sp=0x7f9a052d0e18
runtime.gc.func3()
  /usr/local/go/src/runtime/mgc.go:1089 +0x23 fp=0x7f9a052d0e90 sp=0x7f9a052d0e80
runtime.systemstack(0xc820024000)
  /usr/local/go/src/runtime/asm_amd64.s:262 +0x79 fp=0x7f9a052d0e98 sp=0x7f9a052d0e90
runtime.mstart()
  /usr/local/go/src/runtime/proc1.go:674 fp=0x7f9a052d0ea0 sp=0x7f9a052d0e98

goroutine 66 [garbage collection]:
runtime.systemstack_switch()
  /usr/local/go/src/runtime/asm_amd64.s:216 fp=0xc8201af498 sp=0xc8201af490
runtime.gc(0x0)
  /usr/local/go/src/runtime/mgc.go:1097 +0x3d0 fp=0xc8201af790 sp=0xc8201af498
runtime.backgroundgc()
  /usr/local/go/src/runtime/mgc.go:897 +0x3d fp=0xc8201af7c0 sp=0xc8201af790
runtime.goexit()
  /usr/local/go/src/runtime/asm_amd64.s:1696 +0x1 fp=0xc8201af7c8 sp=0xc8201af7c0
created by runtime.startGC
  /usr/local/go/src/runtime/mgc.go:870 +0x186

[ianlancetaylor]

Thanks. I'm pretty sure this is the same as #13227. When we have a patch for that, it would be great if you could try it with your test case.

[kortschak]

@SergeyTsalkov how long does you case take to fail?