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| author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2017-09-29 05:24:10 -0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2017-09-29 05:24:10 -0400 |
| commit | cf09e3c904bf424f8b6a8203958e09bf7d9bcbc0 (patch) | |
| tree | 5e9936b3de36aa222b52a9bca366a43d98730ffd /Documentation/dev-tools | |
| parent | d5426f4c2ebac8cf05de43988c3fccddbee13d28 (diff) | |
| parent | e19b205be43d11bff638cad4487008c48d21c103 (diff) | |
Merge tag 'v4.14-rc2' into patchwork
Linux 4.14-rc2
* tag 'v4.14-rc2': (12066 commits)
Linux 4.14-rc2
tpm: ibmvtpm: simplify crq initialization and document crq format
tpm: replace msleep() with usleep_range() in TPM 1.2/2.0 generic drivers
Documentation: tpm: add powered-while-suspended binding documentation
tpm: tpm_crb: constify acpi_device_id.
tpm: vtpm: constify vio_device_id
security: fix description of values returned by cap_inode_need_killpriv
x86/asm: Fix inline asm call constraints for Clang
objtool: Handle another GCC stack pointer adjustment bug
inet: fix improper empty comparison
net: use inet6_rcv_saddr to compare sockets
net: set tb->fast_sk_family
net: orphan frags on stand-alone ptype in dev_queue_xmit_nit
MAINTAINERS: update git tree locations for ieee802154 subsystem
SMB3: Don't ignore O_SYNC/O_DSYNC and O_DIRECT flags
SMB3: handle new statx fields
arch: remove unused *_segments() macros/functions
parisc: Unbreak bootloader due to gcc-7 optimizations
parisc: Reintroduce option to gzip-compress the kernel
apparmor: fix apparmorfs DAC access permissions
...
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 |