Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

runtime: pcdata is -2 and 12 locals stack map entries error on nil pointer [1.14 backport] #40647

Open
gopherbot opened this issue Aug 8, 2020 · 2 comments

Comments

@gopherbot
Copy link

@gopherbot gopherbot commented Aug 8, 2020

@randall77 requested issue #40629 to be considered for backport to the next 1.14 minor release.

This patch:

+++ b/src/cmd/compile/internal/ssa/func.go
@@ -274,6 +274,9 @@ func (f *Func) freeValue(v *Value) {
        if len(v.Args) != 0 {
                f.Fatalf("value %s still has %d args", v, len(v.Args))
        }
+       if v == f.LastDeferExit {
+               println("FREEING THE LASTDEFEREXIT")
+       }
        // Clear everything but ID (which we reuse).
        id := v.ID

triggers a bunch of times during make.bash. Both 1.14.2 and tip. Looks like we need to fix this for the release - I think we're just getting lucky that we don't stack copy or gc trace such cases normally (stack copy is only likely to happen with an unrecovered panic?), or that the random other instruction's liveness map is correct (or good enough).

@gopherbot please open a backport issue for 1.14.

1.13 is ok, as open-coded defers were released for 1.14.

@gopherbot
Copy link
Author

@gopherbot gopherbot commented Aug 14, 2020

Change https://golang.org/cl/248622 mentions this issue: cmd/compile: fix live variable computation for deferreturn

@dmitshur dmitshur modified the milestones: Go1.14.8, Go1.14.9 Sep 1, 2020
@dmitshur dmitshur modified the milestones: Go1.14.9, Go1.14.10 Sep 9, 2020
@toothrot
Copy link
Contributor

@toothrot toothrot commented Sep 11, 2020

Approved. This is a serious issue with no workaround.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
Linked pull requests

Successfully merging a pull request may close this issue.

None yet
4 participants
You can’t perform that action at this time.