From 742fda95246958076e439bbcf71fedda43a894bb Mon Sep 17 00:00:00 2001 From: Michael Anthony Knyszek Date: Fri, 27 Jun 2025 00:59:49 +0000 Subject: runtime: account for missing frame pointer in preamble If a goroutine is synchronously preempted, then taking a frame-pointer-based stack trace at that preemption will skip PC of the caller of the function which called into morestack. This happens because the frame pointer is pushed to the stack after the preamble, leaving the stack in an odd state for frame pointer unwinding. Deal with this by marking a goroutine as synchronously preempted and using that signal to load the missing PC from the stack. On LR platforms this is available in gp.sched.lr. On non-LR platforms like x86, it's at gp.sched.sp, because there are no args, no locals, and no frame pointer pushed to the SP yet. For #68090. Change-Id: I73a1206d8b84eecb8a96dbe727195da30088f288 Reviewed-on: https://go-review.googlesource.com/c/go/+/684435 Reviewed-by: Cherry Mui LUCI-TryBot-Result: Go LUCI Reviewed-by: Nick Ripley --- src/runtime/runtime2.go | 1 + 1 file changed, 1 insertion(+) (limited to 'src/runtime/runtime2.go') diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go index 96720846b2..49a2ba2752 100644 --- a/src/runtime/runtime2.go +++ b/src/runtime/runtime2.go @@ -466,6 +466,7 @@ type g struct { runnableTime int64 // the amount of time spent runnable, cleared when running, only used when tracking lockedm muintptr fipsIndicator uint8 + syncSafePoint bool // set if g is stopped at a synchronous safe point. runningCleanups atomic.Bool sig uint32 writebuf []byte -- cgit v1.3