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Steven Rostedt (Google) c42a6e6870 ftrace/scripts: Update the instructions for ftrace-bisect.sh
commit 7ae4ba7195 upstream.

The instructions for the ftrace-bisect.sh script, which is used to find
what function is being traced that is causing a kernel crash, and possibly
a triple fault reboot, uses the old method. In 5.1, a new feature was
added that let the user write in the index into available_filter_functions
that maps to the function a user wants to set in set_ftrace_filter (or
set_ftrace_notrace). This takes O(1) to set, as suppose to writing a
function name, which takes O(n) (where n is the number of functions in
available_filter_functions).

The ftrace-bisect.sh requires setting half of the functions in
available_filter_functions, which is O(n^2) using the name method to enable
and can take several minutes to complete. The number method is O(n) which
takes less than a second to complete. Using the number method for any
kernel 5.1 and after is the proper way to do the bisect.

Update the usage to reflect the new change, as well as using the
/sys/kernel/tracing path instead of the obsolete debugfs path.

Link: https://lkml.kernel.org/r/20230123112252.022003dd@gandalf.local.home

Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Fixes: f79b3f3385 ("ftrace: Allow enabling of filters via index of available_filter_functions")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-01 08:23:22 +01:00
Documentation docs: Fix path paste-o for /sys/kernel/warn_count 2023-02-01 08:23:21 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
arch ia64: make IA64_MCA_RECOVERY bool instead of tristate 2023-02-01 08:23:20 +01:00
block blk-mq: fix possible memleak when register 'hctx' failed 2023-01-14 10:16:19 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:13:17 +02:00
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-14 10:15:50 +01:00
drivers scsi: hpsa: Fix allocation size for scsi_host_alloc() 2023-02-01 08:23:21 +01:00
fs sysctl: add a new register_sysctl_init() interface 2023-02-01 08:23:18 +01:00
include panic: Consolidate open-coded panic_on_warn checks 2023-02-01 08:23:20 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-02 17:40:03 +01:00
io_uring io_uring/rw: remove leftover debug statement 2023-01-24 07:20:02 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:24:00 +01:00
kernel trace_events_hist: add check for return value of 'create_hist_field' 2023-02-01 08:23:22 +01:00
lib panic: Consolidate open-coded panic_on_warn checks 2023-02-01 08:23:20 +01:00
mm panic: Consolidate open-coded panic_on_warn checks 2023-02-01 08:23:20 +01:00
net Bluetooth: hci_sync: cancel cmd_timer if hci_open failed 2023-02-01 08:23:21 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-14 10:16:01 +01:00
scripts ftrace/scripts: Update the instructions for ftrace-bisect.sh 2023-02-01 08:23:22 +01:00
security tomoyo: fix broken dependency on *.conf.default 2023-02-01 08:23:10 +01:00
sound ASoC: fsl-asoc-card: Fix naming of AC'97 CODEC widgets 2023-02-01 08:23:17 +01:00
tools objtool: Add a missing comma to avoid string concatenation 2023-02-01 08:23:19 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt kvm: Add support for arch compat vm ioctls 2022-10-30 09:41:15 +01:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS futex: Move to kernel/futex/ 2023-01-14 10:15:20 +01:00
Makefile Linux 5.10.165 2023-01-24 07:20:02 +01:00
README

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.