Go: off-by-one error in goroutine creation stack

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This program

 1  package main
 2  
 3  func main() {
 4          var x int
 5          ch := make(chan bool, 1)
 6          ch <- true
 7          <-ch
 8          go func() {
 9                  x = 1
10                  ch <- true
11          }()
12          x = 2
13          <-ch
14  }

produces this report:

INFO: T0 is program's main thread
INFO: T1 has been created by T0 at this point: {{{
    #0  main.main ~/go/misc/racecheck/gotsan/race.go:8
    #1  runtime.main ~/go/src/pkg/runtime/proc.c:238
}}}
WARNING: Possible data race during write of size 1 at 0xf840000000: {{{
   T1 (L{}):
    #0  main._func_001 ~/go/misc/racecheck/gotsan/race.go:10
    #1  runtime.goexit ~/go/src/pkg/runtime/proc.c:266
  Concurrent write(s) happened at (OR AFTER) these points:
   T0 (L{}):
    #0  main.main ~/go/misc/racecheck/gotsan/race.go:13
    #1  runtime.main ~/go/src/pkg/runtime/proc.c:238
  Location 0xf840000000 is 0 bytes inside a block starting at 0xf840000000 of size 8 allocated by T0 from heap:
    #0  main.main ~/go/misc/racecheck/gotsan/race.go:5
    #1  runtime.main ~/go/src/pkg/runtime/proc.c:238
}}}

and an even less readable report when lines 6 and 7 commented out

Original issue reported on code.google.com by mpime...@google.com on 16 Jan 2012 at 2:58

[GoogleCodeExporter]

Original comment by mpime...@google.com on 16 Jan 2012 at 2:58

• Added labels: Go
• Removed labels: ****

[GoogleCodeExporter]

Original comment by mpime...@google.com on 3 Apr 2012 at 4:30

• Changed state: Fixed
• Added labels: ****
• Removed labels: ****