diff options
Diffstat (limited to 'src/runtime/checkptr.go')
| -rw-r--r-- | src/runtime/checkptr.go | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/src/runtime/checkptr.go b/src/runtime/checkptr.go index 59891a06a5..d42950844b 100644 --- a/src/runtime/checkptr.go +++ b/src/runtime/checkptr.go @@ -16,11 +16,30 @@ func checkptrAlignment(p unsafe.Pointer, elem *_type, n uintptr) { } // Check that (*[n]elem)(p) doesn't straddle multiple heap objects. - if size := n * elem.size; size > 1 && checkptrBase(p) != checkptrBase(add(p, size-1)) { + // TODO(mdempsky): Fix #46938 so we don't need to worry about overflow here. + if checkptrStraddles(p, n*elem.size) { throw("checkptr: converted pointer straddles multiple allocations") } } +// checkptrStraddles reports whether the first size-bytes of memory +// addressed by ptr is known to straddle more than one Go allocation. +func checkptrStraddles(ptr unsafe.Pointer, size uintptr) bool { + if size <= 1 { + return false + } + + end := add(ptr, size-1) + if uintptr(end) < uintptr(ptr) { + return true + } + + // TODO(mdempsky): Detect when [ptr, end] contains Go allocations, + // but neither ptr nor end point into one themselves. + + return checkptrBase(ptr) != checkptrBase(end) +} + func checkptrArithmetic(p unsafe.Pointer, originals []unsafe.Pointer) { if 0 < uintptr(p) && uintptr(p) < minLegalPointer { throw("checkptr: pointer arithmetic computed bad pointer value") |