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Steven Rostedt (VMware) cbd965bde7 ftrace/selftests: Return the skip code when tracing directory not configured in kernel
If the kernel is not configured with ftrace enabled, the ftracetest
selftests should return the error code of "4" as that is the kselftests
"skip" code, and not "1" which means an error.

To determine if ftrace is enabled, first the newer "tracefs" is searched for
in /proc/mounts. If it is not found, then "debugfs" is searched for (as old
kernels do not have tracefs). If that is not found, an attempt to mount the
tracefs or debugfs is performed. This is done by seeing first if the
/sys/kernel/tracing directory exists. If it does than tracefs is configured
in the kernel and an attempt to mount it is performed.

If /sys/kernel/tracing does not exist, then /sys/kernel/debug is tested to
see if that directory exists. If it does, then an attempt to mount debugfs
on that directory is performed. If it does not exist, then debugfs is not
configured in the running kernel and the test exits with the skip code.

If either mount fails, then a normal error is returned as they do exist in
the kernel but something went wrong to mount them.

This changes the test to always try the tracefs file system first as it has
been in the kernel for some time now and it is better to test it if it is
available instead of always testing debugfs.

Link: http://lkml.kernel.org/r/20190702062358.7330-1-po-hsu.lin@canonical.com

Reported-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-07-16 15:14:47 -04:00
Documentation tracing/kprobe: Add kprobe_event= boot parameter 2019-05-25 23:04:43 -04:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS 2019-05-28 09:36:19 -04:00
block for-5.2/block-post-20190516 2019-05-16 19:08:15 -07:00
certs kexec, KEYS: Make use of platform keyring for signature verify 2019-02-04 17:34:07 -05:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-05-07 22:03:58 -07:00
drivers Kbuild updates for v5.2 (2nd) 2019-05-19 11:53:58 -07:00
fs This pull request contains the following fixes for UBIFS: 2019-05-19 15:22:03 -07:00
include uaccess: Add a prototype of non-static __probe_user_read() 2019-05-25 23:04:43 -04:00
init initramfs: don't free a non-existent initrd 2019-05-18 15:52:26 -07:00
ipc ipc: do cyclic id allocation for the ipc object. 2019-05-14 19:52:52 -07:00
kernel tracing/kprobe: Check registered state using kprobe 2019-07-16 15:14:47 -04:00
lib slab: remove /proc/slab_allocators 2019-05-16 15:51:55 -07:00
mm uaccess: Add non-pagefault user-space read functions 2019-05-25 23:04:42 -04:00
net treewide: prefix header search paths with $(srctree)/ 2019-05-18 11:49:57 +09:00
samples samples: guard sub-directories with CONFIG options 2019-05-18 11:29:01 +09:00
scripts kconfig: use 'else ifneq' for Makefile to improve readability 2019-05-19 09:34:35 +09:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-13 15:15:00 -07:00
sound sound fixes for 5.2-rc1 2019-05-17 13:57:54 -07:00
tools ftrace/selftests: Return the skip code when tracing directory not configured in kernel 2019-07-16 15:14:47 -04:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt * ARM: support for SVE and Pointer Authentication in guests, PMU improvements 2019-05-17 10:33:30 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Kbuild updates for v5.2 (2nd) 2019-05-19 11:53:58 -07:00
Makefile Linux 5.2-rc1 2019-05-19 15:47:09 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.