set_vma_name_linux.go

     1  // Copyright 2025 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build linux
     6  
     7  package runtime
     8  
     9  import (
    10  	"internal/runtime/atomic"
    11  	"internal/runtime/syscall"
    12  	"unsafe"
    13  )
    14  
    15  var prSetVMAUnsupported atomic.Bool
    16  
    17  func setVMANameSupported() bool {
    18  	return !prSetVMAUnsupported.Load()
    19  }
    20  
    21  // setVMAName calls prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, name)
    22  func setVMAName(start unsafe.Pointer, length uintptr, name string) {
    23  	if debug.decoratemappings == 0 || !setVMANameSupported() {
    24  		return
    25  	}
    26  
    27  	var sysName [80]byte
    28  	n := copy(sysName[:], " Go: ")
    29  	copy(sysName[n:79], name) // leave final byte zero
    30  
    31  	_, _, err := syscall.Syscall6(syscall.SYS_PRCTL, syscall.PR_SET_VMA, syscall.PR_SET_VMA_ANON_NAME, uintptr(start), length, uintptr(unsafe.Pointer(&sysName[0])), 0)
    32  	if err == _EINVAL {
    33  		prSetVMAUnsupported.Store(true)
    34  	}
    35  	// ignore other errors
    36  }
    37
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