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Victor Kamensky 9b20065351 perf symbols: Take into account symfs setting when reading file build ID
After commit 5baecbcd9c ("perf symbols: we can now read separate
debug-info files based on a build ID") and when --symfs option is used
perf failed to pick up symbols for file with the same name between host
and sysroot specified by --symfs option.  One can see message like this:

  bin/bash with build id 26f0062cb6950d4d1ab0fd9c43eae8b10ca42062 not found, continuing without symbols

It happens because code added by 5baecbcd9c opens files directly by
dso->long_name without symbol_conf.symfs consideration, which as result
picks one from the host. It reads its build ID and later even code finds
another proper file in directory pointed by --symfs perf ignores it
because build id mismatches.

Fix is to use __symbol__join_symfs to adjust file name according to
--symfs setting. If no --symfs passed the operation would noop and picks
the same host file as before.

Also note in latter tree after 5baecbcd9c commit additional check for
'!dso->has_build_id' was added, so to observe error condition 'perf
record' should run with --no-buildid, so perf.data itself would not have
build id for target binary in buildid perf section and 'perf report'
will pass '!dso->has_build_id' condition. Or target binary should not
have build id, but the same binary on host has build id, again
'!dso->has_build_id' will pass in this case and incorrect build id could
be read if --symfs is used.

Signed-off-by: Victor Kamensky <kamensky@cisco.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Chris Phlipot <cphlipot0@gmail.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: He Kuang <hekuang@huawei.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: xe-linux-external@cisco.com
Fixes: 5baecbcd9c ("perf symbols: we can now read separate debug-info files based on a build ID")
Link: http://lkml.kernel.org/r/1486424908-17094-1-git-send-email-kamensky@cisco.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-02-08 09:28:55 -03:00
Documentation ARC fixes for 4.10-rc6 2017-01-28 11:00:08 -08:00
arch Merge remote-tracking branch 'tip/perf/urgent' into perf/core 2017-02-06 11:09:26 -03:00
block blk-mq: Remove unused variable 2017-01-18 15:14:15 -07:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: api - Clear CRYPTO_ALG_DEAD bit before registering an alg 2017-01-23 22:41:32 +08:00
drivers Merge branch 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-02 13:20:23 -08:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs Three more miscellaneous nfsd bugfixes. 2017-02-02 12:49:58 -08:00
include Merge remote-tracking branch 'tip/perf/urgent' into perf/core 2017-02-06 11:09:26 -03:00
init cgroup: move CONFIG_SOCK_CGROUP_DATA to init/Kconfig 2017-01-11 09:47:10 -05:00
ipc ipc/sem.c: fix incorrect sem_lock pairing 2017-01-10 18:31:55 -08:00
kernel Merge remote-tracking branch 'tip/perf/urgent' into perf/core 2017-02-06 11:09:26 -03:00
lib mm: do not export ioremap_page_range symbol for external module 2017-01-24 16:26:14 -08:00
mm mm, page_alloc: fix premature OOM when racing with cpuset mems update 2017-01-24 16:26:14 -08:00
net Three more miscellaneous nfsd bugfixes. 2017-02-02 12:49:58 -08:00
samples bpf: fix samples xdp_tx_iptunnel and tc_l2_redirect with fake KBUILD_MODNAME 2017-01-20 12:04:07 -05:00
scripts gcc-plugins: update gcc-common.h for gcc-7 2017-01-03 12:08:59 -08:00
security Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sound ASoC: Fixes for v4.10 2017-01-11 19:49:27 +01:00
tools perf symbols: Take into account symfs setting when reading file build ID 2017-02-08 09:28:55 -03:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM updates for 4.10-rc4 2017-01-17 15:04:59 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS CREDITS: Remove outdated address information 2016-12-21 15:21:29 -08:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS wireless-drivers fixes for 4.10 2017-01-30 15:19:23 -05:00
Makefile perf/core improvements and fixes: 2017-02-01 15:33:25 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

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.