linux/tools
Sandipan Das 2a9d5050dc perf script: Show correct offsets for DWARF-based unwinding
When perf/data is recorded with the dwarf call-graph option, the
callchain shown by 'perf script' still shows the binary offsets of the
userspace symbols instead of their virtual addresses. Since the symbol
offset calculation is based on using virtual address as the ip, we see
incorrect offsets as well.

The use of virtual addresses affects the ability to find out the
line number in the corresponding source file to which an address
maps to as described in commit 6754075915 ("perf unwind: Use
addr_location::addr instead of ip for entries").

This has also been addressed by temporarily converting the virtual
address to the correponding binary offset so that it can be mapped
to the source line number correctly.

This is a follow-up for commit 1961018469 ("perf script: Show
virtual addresses instead of offsets").

This can be verified on a powerpc64le system running Fedora 27 as
shown below:

  # perf probe -x /usr/lib64/libc-2.26.so -a inet_pton
  # perf record -e probe_libc:inet_pton --call-graph=dwarf ping -6 -c 1 ::1

Before:

  # perf report --stdio --no-children -s sym,srcline -g address

  # Samples: 1  of event 'probe_libc:inet_pton'
  # Event count (approx.): 1
  #
  # Overhead  Symbol                Source:Line
  # ........  ....................  ...........
  #
     100.00%  [.] __GI___inet_pton  inet_pton.c
              |
              ---gaih_inet getaddrinfo.c:537 (inlined)
                 __GI_getaddrinfo getaddrinfo.c:2304 (inlined)
                 main ping.c:519
                 generic_start_main libc-start.c:308 (inlined)
                 __libc_start_main libc-start.c:102
  ...

  # perf script -F comm,ip,sym,symoff,srcline,dso

  ping
                    15af28 __GI___inet_pton+0xffff000099160008 (/usr/lib64/libc-2.26.so)
    libc-2.26.so[ffff80004ca0af28]
                    10fa53 gaih_inet+0xffff000099160f43
    libc-2.26.so[ffff80004c9bfa53] (inlined)
                    1105b3 __GI_getaddrinfo+0xffff000099160163
    libc-2.26.so[ffff80004c9c05b3] (inlined)
                      2d6f main+0xfffffffd9f1003df (/usr/bin/ping)
    ping[fffffffecf882d6f]
                     2369f generic_start_main+0xffff00009916013f
    libc-2.26.so[ffff80004c8d369f] (inlined)
                     23897 __libc_start_main+0xffff0000991600b7 (/usr/lib64/libc-2.26.so)
    libc-2.26.so[ffff80004c8d3897]

After:

  # perf report --stdio --no-children -s sym,srcline -g address

  # Samples: 1  of event 'probe_libc:inet_pton'
  # Event count (approx.): 1
  #
  # Overhead  Symbol                Source:Line
  # ........  ....................  ...........
  #
     100.00%  [.] __GI___inet_pton  inet_pton.c
              |
              ---gaih_inet.constprop.7 getaddrinfo.c:537
                 getaddrinfo getaddrinfo.c:2304
                 main ping.c:519
                 generic_start_main.isra.0 libc-start.c:308
                 __libc_start_main libc-start.c:102
  ...

  # perf script -F comm,ip,sym,symoff,srcline,dso

  ping
              7fffb38aaf28 __GI___inet_pton+0x8 (/usr/lib64/libc-2.26.so)
    inet_pton.c:68
              7fffb385fa53 gaih_inet.constprop.7+0xf43 (/usr/lib64/libc-2.26.so)
    getaddrinfo.c:537
              7fffb38605b3 getaddrinfo+0x163 (/usr/lib64/libc-2.26.so)
    getaddrinfo.c:2304
                 130782d6f main+0x3df (/usr/bin/ping)
    ping.c:519
              7fffb377369f generic_start_main.isra.0+0x13f (/usr/lib64/libc-2.26.so)
    libc-start.c:308
              7fffb3773897 __libc_start_main+0xb7 (/usr/lib64/libc-2.26.so)
    libc-start.c:102

Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Fixes: 6754075915 ("perf unwind: Use addr_location::addr instead of ip for entries")
Link: http://lkml.kernel.org/r/20180703120555.32971-1-sandipan@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-07-24 14:53:11 -03:00
..
accounting License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
arch tools include: Grab copies of arm64 dependent unistd.h files 2018-07-24 14:52:39 -03:00
bpf tools: bpftool: remember to close the libbpf object after prog load 2018-06-21 23:07:13 +02:00
build tools: build: Use HOSTLDFLAGS with fixdep 2018-07-13 00:48:18 +09:00
cgroup tools: fix cross-compile var clobbering 2018-02-21 15:35:42 -08:00
firewire License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
gpio Linux 4.16-rc5 2018-03-18 17:48:59 +01:00
hv tools: hv: include string.h in hv_fcopy_daemon 2018-03-06 09:57:16 -08:00
iio tools: iio: iio_generic_buffer: allow continuous looping 2018-05-20 14:55:58 +01:00
include tools include: Grab copies of arm64 dependent unistd.h files 2018-07-24 14:52:39 -03:00
kvm/kvm_stat tools/kvm_stat: Remove unused function 2018-03-28 22:47:06 +02:00
laptop tools: fix cross-compile var clobbering 2018-02-21 15:35:42 -08:00
leds tools: fix cross-compile var clobbering 2018-02-21 15:35:42 -08:00
lib docs: Fix some broken references 2018-06-15 18:10:01 -03:00
memory-model tools/memory-model: Add reference for 'Simplifying ARM concurrency' 2018-05-15 08:11:19 +02:00
nfsd License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
objtool objtool: Use '.strtab' if '.shstrtab' doesn't exist, to support ORC tables on Clang 2018-07-14 14:59:42 +02:00
pci License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pcmcia License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
perf perf script: Show correct offsets for DWARF-based unwinding 2018-07-24 14:53:11 -03:00
power Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2018-06-21 00:37:04 +02:00
scripts Kbuild: fix # escaping in .cmd files for future Make 2018-04-11 00:03:02 +09:00
spi tools: fix cross-compile var clobbering 2018-02-21 15:35:42 -08:00
testing Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-07-18 19:32:54 -07:00
thermal/tmon tools/thermal: tmon: fix for segfault 2018-03-27 09:51:23 +02:00
time
usb usbip: usbip_detach: fix to check for invalid ports 2018-05-31 12:44:39 +02:00
virtio sg: remove ->sg_magic member 2018-06-29 08:48:06 -06:00
vm mm: mark pages in use for page tables 2018-06-07 17:34:37 -07:00
wmi tools: fix cross-compile var clobbering 2018-02-21 15:35:42 -08:00
Makefile platform-drivers-x86 for v4.15-1 2017-11-18 10:26:57 -08:00