Go to file
Masami Hiramatsu 5d16dbcc31 perf probe: Fix to probe a function which has no entry pc
Fix 'perf probe' to probe a function which has no entry pc or low pc but
only has ranges attribute.

probe_point_search_cb() uses dwarf_entrypc() to get the probe address,
but that doesn't work for the function DIE which has only ranges
attribute. Use die_entrypc() instead.

Without this fix:

  # perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0
  Probe point 'clear_tasks_mm_cpumask' not found.
    Error: Failed to add events.

With this:

  # perf probe -k ../build-x86_64/vmlinux -D clear_tasks_mm_cpumask:0
  p:probe/clear_tasks_mm_cpumask clear_tasks_mm_cpumask+0

Committer testing:

Before:

  [root@quaco ~]# perf probe clear_tasks_mm_cpumask:0
  Probe point 'clear_tasks_mm_cpumask' not found.
    Error: Failed to add events.
  [root@quaco ~]#

After:

  [root@quaco ~]# perf probe clear_tasks_mm_cpumask:0
  Added new event:
    probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask)

  You can now use it in all perf tools, such as:

  	perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1

  [root@quaco ~]#

Using it with 'perf trace':

  [root@quaco ~]# perf trace -e probe:clear_tasks_mm_cpumask

Doesn't seem to be used in x86_64:

  $ find . -name "*.c" | xargs grep clear_tasks_mm_cpumask
  ./kernel/cpu.c: * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
  ./kernel/cpu.c:void clear_tasks_mm_cpumask(int cpu)
  ./arch/xtensa/kernel/smp.c:	clear_tasks_mm_cpumask(cpu);
  ./arch/csky/kernel/smp.c:	clear_tasks_mm_cpumask(cpu);
  ./arch/sh/kernel/smp.c:	clear_tasks_mm_cpumask(cpu);
  ./arch/arm/kernel/smp.c:	clear_tasks_mm_cpumask(cpu);
  ./arch/powerpc/mm/nohash/mmu_context.c:	clear_tasks_mm_cpumask(cpu);
  $ find . -name "*.h" | xargs grep clear_tasks_mm_cpumask
  ./include/linux/cpu.h:void clear_tasks_mm_cpumask(int cpu);
  $ find . -name "*.S" | xargs grep clear_tasks_mm_cpumask
  $

Fixes: e1ecbbc3fa ("perf probe: Fix to handle optimized not-inlined functions")
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199319438.8075.4695576954550638618.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-11-06 15:43:06 -03:00
arch perf/x86: Synchronize PMU task contexts on optimized context switches 2019-10-28 12:51:01 +01:00
block blk-rq-qos: fix first node deletion of rq_qos_del() 2019-10-15 10:13:13 -06:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation ARM: SoC fixes 2019-10-25 16:00:47 -04:00
drivers Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-10-27 06:55:55 -04:00
fs Seven cifs/smb3 fixes, including three for stable 2019-10-27 06:41:52 -04:00
include perf/core, perf/x86: Introduce swap_task_ctx() method at 'struct pmu' 2019-10-28 12:50:59 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel perf/core: Optimize perf_init_event() for TYPE_SOFTWARE 2019-10-28 12:53:28 +01:00
lib lib/vdso: Make clock_getres() POSIX compliant again 2019-10-23 14:48:23 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/thp: allow dropping THP from page cache 2019-10-19 06:32:33 -04:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-10-19 17:09:11 -04:00
samples Merge branch 'perf/urgent' into perf/core, to pick up fixes 2019-10-28 12:38:26 +01:00
scripts Modules fixes for v5.4-rc5 2019-10-25 16:11:55 -04:00
security perf_event: Add support for LSM and SELinux checks 2019-10-17 21:31:55 +02:00
sound ALSA: hda: Add Tigerlake/Jasperlake PCI ID 2019-10-23 06:28:50 +02:00
tools perf probe: Fix to probe a function which has no entry pc 2019-11-06 15:43:06 -03:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM/arm fixes for 5.4, take #2 2019-10-22 13:31:29 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap A few MIPS fixes: 2019-10-26 19:43:12 -04:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge branch 'perf/urgent' into perf/core, to pick up fixes 2019-10-28 12:38:26 +01:00
Makefile Linux 5.4-rc5 2019-10-27 13:19:19 -04:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.