From 15a274b621b3654e9b4962a27c9d14ea51645b6c Mon Sep 17 00:00:00 2001 From: Cherry Mui Date: Fri, 29 Sep 2023 14:00:04 -0400 Subject: [PATCH] runtime: don't print "unexpected SPWRITE" when printing traceback The system stack often starts with a stack transition function like "systemstack" or "mcall", which is marked as SPWRITE. When unwinding a system stack for printing, we want the traceback stop at the stack switching frame, but not print the "unexpected SPWRITE" message. Previously before CL 525835, we don't print the "unexpected SPWRITE" message if unwindPrintErrors is set, i.e. printing a stack trace. This CL restores this behavior. Another possibility is not printing the message only on the system stack. We don't expect a stack transition function to appear in a user G. Change-Id: I173e89ead2cd4fbf1f0f8cca225f28718b5baebe Reviewed-on: https://go-review.googlesource.com/c/go/+/531815 LUCI-TryBot-Result: Go LUCI Reviewed-by: Michael Pratt Reviewed-by: Michael Knyszek --- src/runtime/crash_unix_test.go | 6 ++++++ src/runtime/traceback.go | 9 +++------ 2 files changed, 9 insertions(+), 6 deletions(-) diff --git a/src/runtime/crash_unix_test.go b/src/runtime/crash_unix_test.go index fbd7626225..123a462423 100644 --- a/src/runtime/crash_unix_test.go +++ b/src/runtime/crash_unix_test.go @@ -216,6 +216,12 @@ func TestPanicSystemstack(t *testing.T) { if nUser != 2 || nSys != 2 { t.Fatalf("want %d user stack frames in %s and %d system stack frames in %s, got %d and %d:\n%s", 2, userFunc, 2, sysFunc, nUser, nSys, string(tb)) } + + // Traceback should not contain "unexpected SPWRITE" when + // unwinding the system stacks. + if bytes.Contains(tb, []byte("unexpected SPWRITE")) { + t.Errorf("unexpected \"unexpected SPWRITE\" in traceback:\n%s", tb) + } } func init() { diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go index 61bb5f57f4..57feefb4a6 100644 --- a/src/runtime/traceback.go +++ b/src/runtime/traceback.go @@ -356,15 +356,12 @@ func (u *unwinder) resolveInternal(innermost, isSyscall bool) { // // uSE uPE inn | action // T _ _ | frame.lr = 0 - // F T F | frame.lr = 0; print - // F T T | frame.lr = 0 + // F T _ | frame.lr = 0 // F F F | print; panic // F F T | ignore SPWrite - if u.flags&unwindSilentErrors == 0 && !innermost { + if u.flags&(unwindPrintErrors|unwindSilentErrors) == 0 && !innermost { println("traceback: unexpected SPWRITE function", funcname(f)) - if u.flags&unwindPrintErrors == 0 { - throw("traceback") - } + throw("traceback") } frame.lr = 0 } else { -- 2.48.1