From 9e8fa1e99c2003cee53a6630aea9d8a3627492ab Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Fri, 17 Jun 2016 11:07:56 -0400 Subject: runtime: eliminate poisonStack checks We haven't used poisonStack since we switched to 1-bit stack maps (4d0f3a1), but the checks are still there. However, nothing prevents us from genuinely allocating an object at this address on 32-bit and causing the runtime to crash claiming that it's found a bad pointer. Since we're not using poisonStack anyway, just pull it out. Fixes #15831. Change-Id: Ia6ef604675b8433f75045e369f5acd4644a5bb38 Reviewed-on: https://go-review.googlesource.com/24211 Run-TryBot: Austin Clements Reviewed-by: Keith Randall --- src/runtime/stack.go | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'src/runtime/stack.go') diff --git a/src/runtime/stack.go b/src/runtime/stack.go index ee2797e144..b14b4005d8 100644 --- a/src/runtime/stack.go +++ b/src/runtime/stack.go @@ -127,7 +127,6 @@ const ( const ( uintptrMask = 1<<(8*sys.PtrSize) - 1 - poisonStack = uintptrMask & 0x6868686868686868 // Goroutine preemption request. // Stored into g->stackguard0 to cause split stack check failure. @@ -594,7 +593,7 @@ func adjustpointers(scanp unsafe.Pointer, cbv *bitvector, adjinfo *adjustinfo, f pp := (*uintptr)(add(scanp, i*sys.PtrSize)) retry: p := *pp - if f != nil && 0 < p && p < _PageSize && debug.invalidptr != 0 || p == poisonStack { + if f != nil && 0 < p && p < _PageSize && debug.invalidptr != 0 { // Looks like a junk value in a pointer slot. // Live analysis wrong? getg().m.traceback = 2 -- cgit v1.3