runtime: fatal error: acquireSudog: found s.elem != nil in cache #10541
Description
Just observed the following crash:
fatal error: acquireSudog: found s.elem != nil in cache
goroutine 54 [running]:
runtime.throw(0x8a6bd0, 0x2a)
src/runtime/panic.go:543 +0x96 fp=0xc209b939a8 sp=0xc209b93990
runtime.acquireSudog(0xc20801edc8)
src/runtime/proc.go:232 +0x456 fp=0xc209b93a48 sp=0xc209b939a8
runtime.chanrecv(0x6ecee0, 0xc20801ed80, 0xc209b93b78, 0x1, 0x0)
src/runtime/chan.go:422 +0x306 fp=0xc209b93b08 sp=0xc209b93a48
runtime.chanrecv1(0x6ecee0, 0xc20801ed80, 0xc209b93b78)
src/runtime/chan.go:335 +0x2b fp=0xc209b93b38 sp=0xc209b93b08
main.(*Testee).shutdown(0xc2081c2380, 0x0, 0x0, 0x0)
src/github.com/dvyukov/go-fuzz/go-fuzz/testee.go:200 +0xd4 fp=0xc209b93b98 sp=0xc209b93b38
main.(*Slave).exec(0xc208188210, 0xc208010380, 0x7, 0xb, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
src/github.com/dvyukov/go-fuzz/go-fuzz/slave.go:344 +0x20a fp=0xc209b93bf8 sp=0xc209b93b98
main.(*Slave).minimizeInput(0xc208188210, 0xc208011c20, 0xb, 0xb, 0x6dc301, 0xc209b93de8, 0x0, 0x0, 0x0)
src/github.com/dvyukov/go-fuzz/go-fuzz/slave.go:179 +0x171 fp=0xc209b93da0 sp=0xc209b93bf8
main.(*Slave).processCrasher(0xc208188210, 0xc208011c20, 0xb, 0xb, 0xc20a505000, 0xbbb, 0xbbb, 0xc208110e40, 0xb4, 0xc0, ...)
src/github.com/dvyukov/go-fuzz/go-fuzz/slave.go:166 +0x93 fp=0xc209b93e58 sp=0xc209b93da0
main.(*Slave).loop(0xc208188210)
src/github.com/dvyukov/go-fuzz/go-fuzz/slave.go:67 +0x124 fp=0xc209b93fd8 sp=0xc209b93e58
runtime.goexit()
src/runtime/asm_amd64.s:1671 +0x1 fp=0xc209b93fe0 sp=0xc209b93fd8
created by main.slaveMain
src/github.com/dvyukov/go-fuzz/go-fuzz/slave.go:56 +0xf6
I see it for the first time.
go version devel +87054c4 Wed Apr 22 02:50:48 2015 +0000 linux/amd64