runtime: in doscanstackswitch, set gp->m before gogo
This is following CL 156038. doscanstackswitch uses the same
mechanism of switching goroutines as getTraceback, and so has
the same problem as described in issue golang/go#29448. This CL
applies the same fix.
Change-Id: I0da9996b0f73755f0171c7c10be6c77cb298b517
Reviewed-on: https://go-review.googlesource.com/c/156697
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c
index 4004df4..1569b5b 100644
--- a/libgo/runtime/proc.c
+++ b/libgo/runtime/proc.c
@@ -482,9 +482,14 @@
void
doscanstackswitch(G* me, G* gp)
{
+ M* holdm;
+
__go_assert(me->entry == nil);
me->fromgogo = false;
+ holdm = gp->m;
+ gp->m = me->m;
+
#ifdef USING_SPLIT_STACK
__splitstack_getcontext((void*)(&me->stackcontext[0]));
#endif
@@ -507,6 +512,8 @@
if (gp->scang != 0)
runtime_gogo(gp);
+
+ gp->m = holdm;
}
// Do a stack scan, then switch back to the g that triggers this scan.
@@ -515,21 +522,15 @@
gscanstack(G *gp)
{
G *oldg, *oldcurg;
- M* holdm;
oldg = (G*)gp->scang;
oldcurg = oldg->m->curg;
- holdm = gp->m;
- if(holdm != nil && holdm != g->m)
- runtime_throw("gscanstack: m is not nil");
oldg->m->curg = gp;
- gp->m = oldg->m;
gp->scang = 0;
doscanstack(gp, (void*)gp->scangcw);
gp->scangcw = 0;
- gp->m = holdm;
oldg->m->curg = oldcurg;
runtime_gogo(oldg);
}
