diff options
| -rw-r--r-- | gcc/go/gofrontend/MERGE | 2 | ||||
| -rw-r--r-- | libgo/go/runtime/proc.go | 18 |
2 files changed, 19 insertions, 1 deletions
diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index 02be610..473eeca 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -29c61dc3c5151df5de9362b7882ccf04679df976 +f107cc8bced1939b0083231fc1ea24669ca4832c The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/libgo/go/runtime/proc.go b/libgo/go/runtime/proc.go index 77b624b..6b6f9c9 100644 --- a/libgo/go/runtime/proc.go +++ b/libgo/go/runtime/proc.go @@ -1097,7 +1097,25 @@ func kickoff() { fv := gp.entry param := gp.param gp.entry = nil + + // When running on the g0 stack we can wind up here without a p, + // for example from mcall(exitsyscall0) in exitsyscall. + // Setting gp.param = nil will call a write barrier, and if + // there is no p that write barrier will crash. When called from + // mcall the gp.param value will be a *g, which we don't need to + // shade since we know it will be kept alive elsewhere. In that + // case clear the field using uintptr so that the write barrier + // does nothing. + if gp.m.p == 0 { + if gp == gp.m.g0 && gp.param == unsafe.Pointer(gp.m.curg) { + *(*uintptr)(unsafe.Pointer(&gp.param)) = 0 + } else { + throw("no p in kickoff") + } + } + gp.param = nil + fv(param) goexit1() } |