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Arnaldo Carvalho de Melo 6c44395455 perf record: Ignore kptr_restrict when not sampling the kernel
If we're not sampling the kernel, we shouldn't care about kptr_restrict
neither synthesize anything for assisting in resolving kernel samples,
like the reference relocation symbol or kernel modules information.

Before:

  $ cat /proc/sys/kernel/kptr_restrict /proc/sys/kernel/perf_event_paranoid
  2
  2
  $ perf record sleep 1
  WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted,
  check /proc/sys/kernel/kptr_restrict.

  Samples in kernel functions may not be resolved if a suitable vmlinux
  file is not found in the buildid cache or in the vmlinux path.

  Samples in kernel modules won't be resolved at all.

  If some relocation was applied (e.g. kexec) symbols may be misresolved
  even with a suitable vmlinux or kallsyms file.

  Couldn't record kernel reference relocation symbol
  Symbol resolution may be skewed if relocation was used (e.g. kexec).
  Check /proc/kallsyms permission or run as root.
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.001 MB perf.data (8 samples) ]
  $ perf evlist -v
  cycles:uppp: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, exclude_kernel: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1
  $

After:

  $ perf record sleep 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.001 MB perf.data (10 samples) ]
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-t025e9zftbx2b8cq2w01g5e5@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-11-16 14:50:02 -03:00
arch Merge remote-tracking branch 'torvalds/master' into perf/core 2017-11-13 09:39:12 -03:00
block License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-11-06 09:05:03 -08:00
Documentation Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
drivers Merge remote-tracking branch 'torvalds/master' into perf/core 2017-11-13 09:39:12 -03:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs fs/hugetlbfs/inode.c: fix hwpoison reserve accounting 2017-11-03 07:39:19 -07:00
include Merge remote-tracking branch 'torvalds/master' into perf/core 2017-11-13 09:39:12 -03:00
init License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel Merge remote-tracking branch 'torvalds/master' into perf/core 2017-11-13 09:39:12 -03:00
lib KEYS: fix NULL pointer dereference during ASN.1 parsing [ver #2] 2017-11-09 00:38:21 +11:00
mm mm, swap: fix race between swap count continuation operations 2017-11-03 07:39:19 -07:00
net vlan: fix a use-after-free in vlan_device_event() 2017-11-11 19:35:32 +09:00
samples Merge branch 'linus' into perf/core, to fix conflicts 2017-11-07 10:30:18 +01:00
scripts modpost: detect modules without a MODULE_LICENSE 2017-11-12 13:47:40 -08:00
security apparmor: fix off-by-one comparison on MAXMAPPED_SIG 2017-11-08 10:56:22 -08:00
sound sound fixes for 4.14 2017-11-09 09:58:11 -08:00
tools perf record: Ignore kptr_restrict when not sampling the kernel 2017-11-16 14:50:02 -03:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt Fixes for interrupt controller emulation in ARM/ARM64 and x86, plus a one-liner 2017-11-04 11:44:55 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14 2017-11-12 10:46:13 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.