diff options
| author | James Morris <james.l.morris@oracle.com> | 2017-09-24 22:41:55 -0700 |
|---|---|---|
| committer | James Morris <james.l.morris@oracle.com> | 2017-09-24 22:41:55 -0700 |
| commit | 25eabb13c7d67ae32298015c5e28d00f604f412c (patch) | |
| tree | 5bd75c2c1e385c79425bb099f0d19db7fb9c391f /Documentation/dev-tools | |
| parent | ab5348c9c23cd253f5902980d2d8fe067dc24c82 (diff) | |
| parent | e19b205be43d11bff638cad4487008c48d21c103 (diff) | |
Merge tag 'v4.14-rc2' into next-general
Linux 4.14-rc2
Sync to v4.14-rc2 for security subsystem developers to track.
Diffstat (limited to 'Documentation/dev-tools')
| -rw-r--r-- | Documentation/dev-tools/gdb-kernel-debugging.rst | 6 | ||||
| -rw-r--r-- | Documentation/dev-tools/kgdb.rst | 11 |
2 files changed, 14 insertions, 3 deletions
diff --git a/Documentation/dev-tools/gdb-kernel-debugging.rst b/Documentation/dev-tools/gdb-kernel-debugging.rst index 5e93c9bc6619..19df79286f00 100644 --- a/Documentation/dev-tools/gdb-kernel-debugging.rst +++ b/Documentation/dev-tools/gdb-kernel-debugging.rst @@ -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 diff --git a/Documentation/dev-tools/kgdb.rst b/Documentation/dev-tools/kgdb.rst index 75273203a35a..d38be58f872a 100644 --- a/Documentation/dev-tools/kgdb.rst +++ b/Documentation/dev-tools/kgdb.rst @@ -348,6 +348,15 @@ default behavior is always set to 0. - ``echo 1 > /sys/module/debug_core/parameters/kgdbreboot`` - Enter the debugger on reboot notify. +Kernel parameter: ``nokaslr`` +----------------------------- + +If the architecture that you are using enable KASLR by default, +you should consider turning it off. KASLR randomizes the +virtual address where the kernel image is mapped and confuse +gdb which resolve kernel symbol address from symbol table +of vmlinux. + Using kdb ========= @@ -358,7 +367,7 @@ This is a quick example of how to use kdb. 1. Configure kgdboc at boot using kernel parameters:: - console=ttyS0,115200 kgdboc=ttyS0,115200 + console=ttyS0,115200 kgdboc=ttyS0,115200 nokaslr OR |