Commit e604f1cb authored by Zhouyi Zhou's avatar Zhouyi Zhou Committed by Jonathan Corbet
Browse files

docs: disable KASLR when debugging kernel 



commit 6807c846 ("x86: Enable KASLR by default") enables KASLR
by default on x86. While KASLR will confuse gdb which resolve kernel
symbol address from symbol table of vmlinux. We should turn off KASLR for
kernel debugging.

Signed-off-by: default avatarZhouyi Zhou <zhouzhouyi@gmail.com>
Reviewed-by: default avatarKieran Bingham <kbingham@kernel.org>
Acked-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 14994a9b

Documentation/dev-tools/gdb-kernel-debugging.rst

+4 −2
Original line number Diff line number Diff line
@@ -31,11 +31,13 @@ Setup 
  CONFIG_DEBUG_INFO_REDUCED off. If your architecture supports

  CONFIG_FRAME_POINTER, keep it enabled.



- Install that kernel on the guest.

- Install that kernel on the guest, turn off KASLR if necessary by adding

  "nokaslr" to the kernel command line.

  Alternatively, QEMU allows to boot the kernel directly using -kernel,

  -append, -initrd command line switches. This is generally only useful if

  you do not depend on modules. See QEMU documentation for more details on

  this mode.

  this mode. In this case, you should build the kernel with

  CONFIG_RANDOMIZE_BASE disabled if the architecture supports KASLR.



- Enable the gdb stub of QEMU/KVM, either