runtime: zero saved frame pointer when reusing goroutine stack on arm64
When a goroutine stack is reused on arm64, the spot on the stack where
the "caller's" frame pointer goes for the topmost frame should be
explicitly zeroed. Otherwise, the frame pointer check in adjustframe
with debugCheckBP enabled will fail on the topmost frame of a call stack
the first time a reused stack is grown.
Updates #39524, #58432
Change-Id: Ic1210dc005e3ecdbf9cd5d7b98846566e56df8f5
Reviewed-on: https://go-review.googlesource.com/c/go/+/481636 Reviewed-by: Felix Geisendörfer <felix.geisendoerfer@datadoghq.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>