From 66f78e9d885e9a8ed7f8d2432d9f08bb586dd7cb Mon Sep 17 00:00:00 2001 From: Cuong Manh Le Date: Wed, 23 Oct 2019 14:31:29 +0700 Subject: [PATCH] runtime: mark findObject nosplit findObject takes the pointer argument as uintptr. If the pointer is to the local stack and calling findObject happens to require the stack to be reallocated, then spanOf is called for the old pointer. Marking findObject as nosplit fixes the issue. Fixes #35068 Change-Id: I029d36f9c23f91812f18f98839edf02e0ba4082e Reviewed-on: https://go-review.googlesource.com/c/go/+/202798 Run-TryBot: Cuong Manh Le TryBot-Result: Gobot Gobot Reviewed-by: Austin Clements --- src/runtime/mbitmap.go | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/runtime/mbitmap.go b/src/runtime/mbitmap.go index 68a22690d2..d131bab600 100644 --- a/src/runtime/mbitmap.go +++ b/src/runtime/mbitmap.go @@ -385,6 +385,10 @@ func badPointer(s *mspan, p, refBase, refOff uintptr) { // refBase and refOff optionally give the base address of the object // in which the pointer p was found and the byte offset at which it // was found. These are used for error reporting. +// +// It is nosplit so it is safe for p to be a pointer to the current goroutine's stack. +// Since p is a uintptr, it would not be adjusted if the stack were to move. +//go:nosplit func findObject(p, refBase, refOff uintptr) (base uintptr, s *mspan, objIndex uintptr) { s = spanOf(p) // If s is nil, the virtual address has never been part of the heap.