runtime: writebarrierptr panic in isolated code snippet on Go 1.8.3 #21897
Description
What version of Go are you using (go version)?
1.8.3.
Does this issue reproduce with the latest release?
The issue does not repro with 1.9
What operating system and processor architecture are you using (go env)?
Repro'ed on macOS and linux.
What did you do?
package main
import (
"fmt"
"unsafe"
"time"
)
func main() {
for i := 0; i < 1000000; i++ {
x := unsafe.Pointer(uintptr(0x27))
fmt.Printf("%p\n", x)
time.Sleep(1)
}
}What did you expect to see?
No crash
What did you see instead?
....
0x27
0x27
0x27
0x27
0x27
0x27
runtime: writebarrierptr *0xc4200e80e0 = 0x27
fatal error: bad pointer in write barrier
runtime stack:
runtime.throw(0x10b6a19, 0x1c)
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/panic.go:596 +0x95
runtime.writebarrierptr.func1()
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/mbarrier.go:208 +0xbd
runtime.systemstack(0xc42001e600)
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/asm_amd64.s:327 +0x79
runtime.mstart()
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/proc.go:1132
goroutine 1 [running]:
runtime.systemstack_switch()
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/asm_amd64.s:281 fp=0xc420042cb8 sp=0xc420042cb0
runtime.writebarrierptr(0xc4200e80e0, 0x27)
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/mbarrier.go:209 +0x96 fp=0xc420042cf0 sp=0xc420042cb8
fmt.(*pp).printArg(0xc4200e80c0, 0x1097480, 0x27, 0x70)
/usr/local/Cellar/go/1.8.3/libexec/src/fmt/print.go:605 +0xa10 fp=0xc420042d78 sp=0xc420042cf0
fmt.(*pp).doPrintf(0xc4200e80c0, 0x10b37d3, 0x3, 0xc420042f68, 0x1, 0x1)
/usr/local/Cellar/go/1.8.3/libexec/src/fmt/print.go:998 +0x11e7 fp=0xc420042e58 sp=0xc420042d78
fmt.Fprintf(0x110a140, 0xc42000c018, 0x10b37d3, 0x3, 0xc420042f68, 0x1, 0x1, 0x13, 0x2, 0xc420446000)
/usr/local/Cellar/go/1.8.3/libexec/src/fmt/print.go:181 +0x76 fp=0xc420042ec0 sp=0xc420042e58
fmt.Printf(0x10b37d3, 0x3, 0xc420042f68, 0x1, 0x1, 0x5, 0x0, 0x0)
/usr/local/Cellar/go/1.8.3/libexec/src/fmt/print.go:190 +0x72 fp=0xc420042f20 sp=0xc420042ec0
main.main()
/Users/max/src/go/src/play/play.go:12 +0x8c fp=0xc420042f88 sp=0xc420042f20
runtime.main()
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/proc.go:185 +0x20a fp=0xc420042fe0 sp=0xc420042f88
runtime.goexit()
/usr/local/Cellar/go/1.8.3/libexec/src/runtime/asm_amd64.s:2197 +0x1 fp=0xc420042fe8 sp=0xc420042fe0