License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
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// SPDX-License-Identifier: GPL-2.0
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2014-02-19 15:52:57 +00:00
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#include <linux/compiler.h>
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#include <elfutils/libdw.h>
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#include <elfutils/libdwfl.h>
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#include <inttypes.h>
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#include <errno.h>
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2014-07-14 21:46:48 +00:00
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#include "debug.h"
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2014-02-19 15:52:57 +00:00
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#include "unwind.h"
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#include "unwind-libdw.h"
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#include "machine.h"
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2019-01-27 12:42:37 +00:00
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#include "map.h"
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2014-02-19 15:52:57 +00:00
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#include "thread.h"
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2014-04-25 19:31:02 +00:00
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#include <linux/types.h>
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2014-02-19 15:52:57 +00:00
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#include "event.h"
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#include "perf_regs.h"
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2015-11-19 13:01:19 +00:00
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#include "callchain.h"
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2017-04-18 14:33:48 +00:00
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#include "util.h"
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2014-02-19 15:52:57 +00:00
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static char *debuginfo_path;
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static const Dwfl_Callbacks offline_callbacks = {
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.find_debuginfo = dwfl_standard_find_debuginfo,
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.debuginfo_path = &debuginfo_path,
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.section_address = dwfl_offline_section_address,
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};
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static int __report_module(struct addr_location *al, u64 ip,
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struct unwind_info *ui)
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{
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Dwfl_Module *mod;
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struct dso *dso = NULL;
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2018-04-24 14:24:49 +00:00
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/*
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* Some callers will use al->sym, so we can't just use the
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* cheaper thread__find_map() here.
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*/
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thread__find_symbol(ui->thread, PERF_RECORD_MISC_USER, ip, al);
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2014-02-19 15:52:57 +00:00
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if (al->map)
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dso = al->map->dso;
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if (!dso)
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return 0;
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mod = dwfl_addrmodule(ui->dwfl, ip);
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2017-06-02 14:37:52 +00:00
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if (mod) {
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Dwarf_Addr s;
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dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL);
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perf unwind: Take pgoff into account when reporting elf to libdwfl
libdwfl parses an ELF file itself and creates mappings for the
individual sections. perf on the other hand sees raw mmap events which
represent individual sections. When we encounter an address pointing
into a mapping with pgoff != 0, we must take that into account and
report the file at the non-offset base address.
This fixes unwinding with libdwfl in some cases. E.g. for a file like:
```
using namespace std;
mutex g_mutex;
double worker()
{
lock_guard<mutex> guard(g_mutex);
uniform_real_distribution<double> uniform(-1E5, 1E5);
default_random_engine engine;
double s = 0;
for (int i = 0; i < 1000; ++i) {
s += norm(complex<double>(uniform(engine), uniform(engine)));
}
cout << s << endl;
return s;
}
int main()
{
vector<std::future<double>> results;
for (int i = 0; i < 10000; ++i) {
results.push_back(async(launch::async, worker));
}
return 0;
}
```
Compile it with `g++ -g -O2 -lpthread cpp-locking.cpp -o cpp-locking`,
then record it with `perf record --call-graph dwarf -e
sched:sched_switch`.
When you analyze it with `perf script` and libunwind, you should see:
```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so)
7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so)
7f38e42569e5 __GI___libc_malloc+0x115 (inlined)
7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined)
7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined)
7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined)
7f38e424df36 _IO_new_file_xsputn+0x116 (inlined)
7f38e4242bfb __GI__IO_fwrite+0xdb (inlined)
7f38e463fa6d std::basic_streambuf<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(double)+0x90 (/usr/lib/libstdc++.so.6.0.25)
563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined)
563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking)
563b9cb506fb double std::__invoke_impl<double, double (*)()>(std::__invoke_other, double (*&&)())+0x2b (inlined)
563b9cb506fb std::__invoke_result<double (*)()>::type std::__invoke<double (*)()>(double (*&&)())+0x2b (inlined)
563b9cb506fb decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<double (*)()> >::_M_invoke<0ul>(std::_Index_tuple<0ul>)+0x2b (inlined)
563b9cb506fb std::thread::_Invoker<std::tuple<double (*)()> >::operator()()+0x2b (inlined)
563b9cb506fb std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<double>, std::__future_base::_Result_base::_Deleter>, std::thread::_Invoker<std::tuple<double (*)()> >, dou>
563b9cb506fb std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_>
563b9cb507e8 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const+0x28 (inlined)
563b9cb507e8 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)+0x28 (/ssd/milian/>
7f38e46d24fe __pthread_once_slow+0xbe (/usr/lib/libpthread-2.28.so)
563b9cb51149 __gthread_once+0xe9 (inlined)
563b9cb51149 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)>
563b9cb51149 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool)+0xe9 (inlined)
563b9cb51149 std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >&&)::{lambda()#1}::op>
563b9cb51149 void std::__invoke_impl<void, std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double>
563b9cb51149 std::__invoke_result<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >>
563b9cb51149 decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_>
563b9cb51149 std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<dou>
563b9cb51149 std::thread::_State_impl<std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread>
7f38e45f0062 execute_native_thread_routine+0x12 (/usr/lib/libstdc++.so.6.0.25)
7f38e46caa9c start_thread+0xfc (/usr/lib/libpthread-2.28.so)
7f38e42ccb22 __GI___clone+0x42 (inlined)
```
Before this patch, using libdwfl, you would see:
```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
a041161e77950c5c [unknown] ([unknown])
```
With this patch applied, we get a bit further in unwinding:
```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so)
7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so)
7f38e42569e5 __GI___libc_malloc+0x115 (inlined)
7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined)
7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined)
7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined)
7f38e424df36 _IO_new_file_xsputn+0x116 (inlined)
7f38e4242bfb __GI__IO_fwrite+0xdb (inlined)
7f38e463fa6d std::basic_streambuf<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(double)+0x90 (/usr/lib/libstdc++.so.6.0.25)
563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined)
563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking)
6eab825c1ee3e4ff [unknown] ([unknown])
```
Note that the backtrace is still stopping too early, when compared to
the nice results obtained via libunwind. It's unclear so far what the
reason for that is.
Committer note:
Further comment by Milian on the thread started on the Link: tag below:
---
The remaining issue is due to a bug in elfutils:
https://sourceware.org/ml/elfutils-devel/2018-q4/msg00089.html
With both patches applied, libunwind and elfutils produce the same output for
the above scenario.
---
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20181029141644.3907-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-10-29 14:16:44 +00:00
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if (s != al->map->start - al->map->pgoff)
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2017-06-02 14:37:52 +00:00
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mod = 0;
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}
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2014-02-19 15:52:57 +00:00
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if (!mod)
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mod = dwfl_report_elf(ui->dwfl, dso->short_name,
|
perf unwind: Take pgoff into account when reporting elf to libdwfl
libdwfl parses an ELF file itself and creates mappings for the
individual sections. perf on the other hand sees raw mmap events which
represent individual sections. When we encounter an address pointing
into a mapping with pgoff != 0, we must take that into account and
report the file at the non-offset base address.
This fixes unwinding with libdwfl in some cases. E.g. for a file like:
```
using namespace std;
mutex g_mutex;
double worker()
{
lock_guard<mutex> guard(g_mutex);
uniform_real_distribution<double> uniform(-1E5, 1E5);
default_random_engine engine;
double s = 0;
for (int i = 0; i < 1000; ++i) {
s += norm(complex<double>(uniform(engine), uniform(engine)));
}
cout << s << endl;
return s;
}
int main()
{
vector<std::future<double>> results;
for (int i = 0; i < 10000; ++i) {
results.push_back(async(launch::async, worker));
}
return 0;
}
```
Compile it with `g++ -g -O2 -lpthread cpp-locking.cpp -o cpp-locking`,
then record it with `perf record --call-graph dwarf -e
sched:sched_switch`.
When you analyze it with `perf script` and libunwind, you should see:
```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so)
7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so)
7f38e42569e5 __GI___libc_malloc+0x115 (inlined)
7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined)
7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined)
7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined)
7f38e424df36 _IO_new_file_xsputn+0x116 (inlined)
7f38e4242bfb __GI__IO_fwrite+0xdb (inlined)
7f38e463fa6d std::basic_streambuf<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(double)+0x90 (/usr/lib/libstdc++.so.6.0.25)
563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined)
563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking)
563b9cb506fb double std::__invoke_impl<double, double (*)()>(std::__invoke_other, double (*&&)())+0x2b (inlined)
563b9cb506fb std::__invoke_result<double (*)()>::type std::__invoke<double (*)()>(double (*&&)())+0x2b (inlined)
563b9cb506fb decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<double (*)()> >::_M_invoke<0ul>(std::_Index_tuple<0ul>)+0x2b (inlined)
563b9cb506fb std::thread::_Invoker<std::tuple<double (*)()> >::operator()()+0x2b (inlined)
563b9cb506fb std::__future_base::_Task_setter<std::unique_ptr<std::__future_base::_Result<double>, std::__future_base::_Result_base::_Deleter>, std::thread::_Invoker<std::tuple<double (*)()> >, dou>
563b9cb506fb std::_Function_handler<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> (), std::__future_base::_Task_setter<std::unique_ptr<std::__future_>
563b9cb507e8 std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>::operator()() const+0x28 (inlined)
563b9cb507e8 std::__future_base::_State_baseV2::_M_do_set(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)+0x28 (/ssd/milian/>
7f38e46d24fe __pthread_once_slow+0xbe (/usr/lib/libpthread-2.28.so)
563b9cb51149 __gthread_once+0xe9 (inlined)
563b9cb51149 void std::call_once<void (std::__future_base::_State_baseV2::*)(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>*, bool*)>
563b9cb51149 std::__future_base::_State_baseV2::_M_set_result(std::function<std::unique_ptr<std::__future_base::_Result_base, std::__future_base::_Result_base::_Deleter> ()>, bool)+0xe9 (inlined)
563b9cb51149 std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >&&)::{lambda()#1}::op>
563b9cb51149 void std::__invoke_impl<void, std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double>
563b9cb51149 std::__invoke_result<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<double (*)()> >>
563b9cb51149 decltype (__invoke((_S_declval<0ul>)())) std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_>
563b9cb51149 std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread::_Invoker<std::tuple<dou>
563b9cb51149 std::thread::_State_impl<std::thread::_Invoker<std::tuple<std::__future_base::_Async_state_impl<std::thread::_Invoker<std::tuple<double (*)()> >, double>::_Async_state_impl(std::thread>
7f38e45f0062 execute_native_thread_routine+0x12 (/usr/lib/libstdc++.so.6.0.25)
7f38e46caa9c start_thread+0xfc (/usr/lib/libpthread-2.28.so)
7f38e42ccb22 __GI___clone+0x42 (inlined)
```
Before this patch, using libdwfl, you would see:
```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
a041161e77950c5c [unknown] ([unknown])
```
With this patch applied, we get a bit further in unwinding:
```
cpp-locking 20038 [005] 54830.236589: sched:sched_switch: prev_comm=cpp-locking prev_pid=20038 prev_prio=120 prev_state=T ==> next_comm=swapper/5 next_pid=0 next_prio=120
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb166fec5 __sched_text_start+0x545 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1670208 schedule+0x28 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb16737cc rwsem_down_read_failed+0xec (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1665e04 call_rwsem_down_read_failed+0x14 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb1672a03 down_read+0x13 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb106bd85 __do_page_fault+0x445 (/lib/modules/4.14.78-1-lts/build/vmlinux)
ffffffffb18015f5 page_fault+0x45 (/lib/modules/4.14.78-1-lts/build/vmlinux)
7f38e4252591 new_heap+0x101 (/usr/lib/libc-2.28.so)
7f38e4252d0b arena_get2.part.4+0x2fb (/usr/lib/libc-2.28.so)
7f38e4255b1c tcache_init.part.6+0xec (/usr/lib/libc-2.28.so)
7f38e42569e5 __GI___libc_malloc+0x115 (inlined)
7f38e4241790 __GI__IO_file_doallocate+0x90 (inlined)
7f38e424fbbf __GI__IO_doallocbuf+0x4f (inlined)
7f38e424ee47 __GI__IO_file_overflow+0x197 (inlined)
7f38e424df36 _IO_new_file_xsputn+0x116 (inlined)
7f38e4242bfb __GI__IO_fwrite+0xdb (inlined)
7f38e463fa6d std::basic_streambuf<char, std::char_traits<char> >::sputn(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> >::_M_put(char const*, long)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::__write<char>(std::ostreambuf_iterator<char, std::char_traits<char> >, char const*, int)+0x1cd (inlined)
7f38e463fa6d std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_float<double>(std::ostreambuf_iterator<c>
7f38e464bd70 std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, double) const+0x90 (inl>
7f38e464bd70 std::ostream& std::ostream::_M_insert<double>(double)+0x90 (/usr/lib/libstdc++.so.6.0.25)
563b9cb502f7 std::ostream::operator<<(double)+0xb7 (inlined)
563b9cb502f7 worker()+0xb7 (/ssd/milian/projects/kdab/rnd/hotspot/build/tests/test-clients/cpp-locking/cpp-locking)
6eab825c1ee3e4ff [unknown] ([unknown])
```
Note that the backtrace is still stopping too early, when compared to
the nice results obtained via libunwind. It's unclear so far what the
reason for that is.
Committer note:
Further comment by Milian on the thread started on the Link: tag below:
---
The remaining issue is due to a bug in elfutils:
https://sourceware.org/ml/elfutils-devel/2018-q4/msg00089.html
With both patches applied, libunwind and elfutils produce the same output for
the above scenario.
---
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20181029141644.3907-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-10-29 14:16:44 +00:00
|
|
|
(dso->symsrc_filename ? dso->symsrc_filename : dso->long_name), -1, al->map->start - al->map->pgoff,
|
2014-02-19 15:52:57 +00:00
|
|
|
false);
|
|
|
|
|
|
|
|
return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int report_module(u64 ip, struct unwind_info *ui)
|
|
|
|
{
|
|
|
|
struct addr_location al;
|
|
|
|
|
|
|
|
return __report_module(&al, ip, ui);
|
|
|
|
}
|
|
|
|
|
2015-11-19 13:01:19 +00:00
|
|
|
/*
|
|
|
|
* Store all entries within entries array,
|
|
|
|
* we will process it after we finish unwind.
|
|
|
|
*/
|
2014-02-19 15:52:57 +00:00
|
|
|
static int entry(u64 ip, struct unwind_info *ui)
|
|
|
|
|
|
|
|
{
|
2015-11-19 13:01:19 +00:00
|
|
|
struct unwind_entry *e = &ui->entries[ui->idx++];
|
2014-02-19 15:52:57 +00:00
|
|
|
struct addr_location al;
|
|
|
|
|
|
|
|
if (__report_module(&al, ip, ui))
|
|
|
|
return -1;
|
|
|
|
|
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 67540759151a ("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 19610184693c ("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: 67540759151a ("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>
2018-07-03 12:05:55 +00:00
|
|
|
e->ip = ip;
|
2015-11-19 13:01:19 +00:00
|
|
|
e->map = al.map;
|
|
|
|
e->sym = al.sym;
|
2014-02-19 15:52:57 +00:00
|
|
|
|
|
|
|
pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
|
|
|
|
al.sym ? al.sym->name : "''",
|
|
|
|
ip,
|
|
|
|
al.map ? al.map->map_ip(al.map, ip) : (u64) 0);
|
2015-11-19 13:01:19 +00:00
|
|
|
return 0;
|
2014-02-19 15:52:57 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp)
|
|
|
|
{
|
|
|
|
/* We want only single thread to be processed. */
|
|
|
|
if (*thread_argp != NULL)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
*thread_argp = arg;
|
|
|
|
return dwfl_pid(dwfl);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr,
|
|
|
|
Dwarf_Word *data)
|
|
|
|
{
|
|
|
|
struct addr_location al;
|
|
|
|
ssize_t size;
|
|
|
|
|
2018-04-24 14:58:56 +00:00
|
|
|
if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) {
|
2014-02-19 15:52:57 +00:00
|
|
|
pr_debug("unwind: no map for %lx\n", (unsigned long)addr);
|
|
|
|
return -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!al.map->dso)
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
size = dso__data_read_addr(al.map->dso, al.map, ui->machine,
|
|
|
|
addr, (u8 *) data, sizeof(*data));
|
|
|
|
|
|
|
|
return !(size == sizeof(*data));
|
|
|
|
}
|
|
|
|
|
|
|
|
static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result,
|
|
|
|
void *arg)
|
|
|
|
{
|
|
|
|
struct unwind_info *ui = arg;
|
|
|
|
struct stack_dump *stack = &ui->sample->user_stack;
|
|
|
|
u64 start, end;
|
|
|
|
int offset;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP);
|
|
|
|
if (ret)
|
|
|
|
return false;
|
|
|
|
|
|
|
|
end = start + stack->size;
|
|
|
|
|
|
|
|
/* Check overflow. */
|
|
|
|
if (addr + sizeof(Dwarf_Word) < addr)
|
|
|
|
return false;
|
|
|
|
|
|
|
|
if (addr < start || addr + sizeof(Dwarf_Word) > end) {
|
|
|
|
ret = access_dso_mem(ui, addr, result);
|
|
|
|
if (ret) {
|
|
|
|
pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range"
|
|
|
|
" 0x%" PRIx64 "-0x%" PRIx64 "\n",
|
|
|
|
addr, start, end);
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
offset = addr - start;
|
|
|
|
*result = *(Dwarf_Word *)&stack->data[offset];
|
|
|
|
pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n",
|
|
|
|
addr, (unsigned long)*result, offset);
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
static const Dwfl_Thread_Callbacks callbacks = {
|
|
|
|
.next_thread = next_thread,
|
|
|
|
.memory_read = memory_read,
|
|
|
|
.set_initial_registers = libdw__arch_set_initial_registers,
|
|
|
|
};
|
|
|
|
|
|
|
|
static int
|
|
|
|
frame_callback(Dwfl_Frame *state, void *arg)
|
|
|
|
{
|
|
|
|
struct unwind_info *ui = arg;
|
|
|
|
Dwarf_Addr pc;
|
perf report: Fix off-by-one for non-activation frames
As the documentation for dwfl_frame_pc says, frames that
are no activation frames need to have their program counter
decremented by one to properly find the function of the caller.
This fixes many cases where perf report currently attributes
the cost to the next line. I.e. I have code like this:
~~~~~~~~~~~~~~~
#include <thread>
#include <chrono>
using namespace std;
int main()
{
this_thread::sleep_for(chrono::milliseconds(1000));
this_thread::sleep_for(chrono::milliseconds(100));
this_thread::sleep_for(chrono::milliseconds(10));
return 0;
}
~~~~~~~~~~~~~~~
Now compile and record it:
~~~~~~~~~~~~~~~
g++ -std=c++11 -g -O2 test.cpp
echo 1 | sudo tee /proc/sys/kernel/sched_schedstats
perf record \
--event sched:sched_stat_sleep \
--event sched:sched_process_exit \
--event sched:sched_switch --call-graph=dwarf \
--output perf.data.raw \
./a.out
echo 0 | sudo tee /proc/sys/kernel/sched_schedstats
perf inject --sched-stat --input perf.data.raw --output perf.data
~~~~~~~~~~~~~~~
Before this patch, the report clearly shows the off-by-one issue.
Most notably, the last sleep invocation is incorrectly attributed
to the "return 0;" line:
~~~~~~~~~~~~~~~
Overhead Source:Line
........ ...........
100.00% core.c:0
|
---__schedule core.c:0
schedule
do_nanosleep hrtimer.c:0
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath .tmp_entry_64.o:0
__nanosleep_nocancel .:0
std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > thread:323
|
|--90.08%--main test.cpp:9
| __libc_start_main
| _start
|
|--9.01%--main test.cpp:10
| __libc_start_main
| _start
|
--0.91%--main test.cpp:13
__libc_start_main
_start
~~~~~~~~~~~~~~~
With this patch here applied, the issue is fixed. The report becomes
much more usable:
~~~~~~~~~~~~~~~
Overhead Source:Line
........ ...........
100.00% core.c:0
|
---__schedule core.c:0
schedule
do_nanosleep hrtimer.c:0
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath .tmp_entry_64.o:0
__nanosleep_nocancel .:0
std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > thread:323
|
|--90.08%--main test.cpp:8
| __libc_start_main
| _start
|
|--9.01%--main test.cpp:9
| __libc_start_main
| _start
|
--0.91%--main test.cpp:10
__libc_start_main
_start
~~~~~~~~~~~~~~~
Similarly it works for signal frames:
~~~~~~~~~~~~~~~
__noinline void bar(void)
{
volatile long cnt = 0;
for (cnt = 0; cnt < 100000000; cnt++);
}
__noinline void foo(void)
{
bar();
}
void sig_handler(int sig)
{
foo();
}
int main(void)
{
signal(SIGUSR1, sig_handler);
raise(SIGUSR1);
foo();
return 0;
}
~~~~~~~~~~~~~~~~
Before, the report wrongly points to `signal.c:29` after raise():
~~~~~~~~~~~~~~~~
$ perf report --stdio --no-children -g srcline -s srcline
...
100.00% signal.c:11
|
---bar signal.c:11
|
|--50.49%--main signal.c:29
| __libc_start_main
| _start
|
--49.51%--0x33a8f
raise .:0
main signal.c:29
__libc_start_main
_start
~~~~~~~~~~~~~~~~
With this patch in, the issue is fixed and we instead get:
~~~~~~~~~~~~~~~~
100.00% signal signal [.] bar
|
---bar signal.c:11
|
|--50.49%--main signal.c:29
| __libc_start_main
| _start
|
--49.51%--0x33a8f
raise .:0
main signal.c:27
__libc_start_main
_start
~~~~~~~~~~~~~~~~
Note how this patch fixes this issue for both unwinding methods, i.e.
both dwfl and libunwind. The former case is straight-forward thanks
to dwfl_frame_pc(). For libunwind, we replace the functionality via
unw_is_signal_frame() for any but the very first frame.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yao Jin <yao.jin@linux.intel.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170524062129.32529-4-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-24 06:21:25 +00:00
|
|
|
bool isactivation;
|
2014-02-19 15:52:57 +00:00
|
|
|
|
2017-06-02 14:37:53 +00:00
|
|
|
if (!dwfl_frame_pc(state, &pc, NULL)) {
|
|
|
|
pr_err("%s", dwfl_errmsg(-1));
|
|
|
|
return DWARF_CB_ABORT;
|
|
|
|
}
|
|
|
|
|
|
|
|
// report the module before we query for isactivation
|
|
|
|
report_module(pc, ui);
|
|
|
|
|
perf report: Fix off-by-one for non-activation frames
As the documentation for dwfl_frame_pc says, frames that
are no activation frames need to have their program counter
decremented by one to properly find the function of the caller.
This fixes many cases where perf report currently attributes
the cost to the next line. I.e. I have code like this:
~~~~~~~~~~~~~~~
#include <thread>
#include <chrono>
using namespace std;
int main()
{
this_thread::sleep_for(chrono::milliseconds(1000));
this_thread::sleep_for(chrono::milliseconds(100));
this_thread::sleep_for(chrono::milliseconds(10));
return 0;
}
~~~~~~~~~~~~~~~
Now compile and record it:
~~~~~~~~~~~~~~~
g++ -std=c++11 -g -O2 test.cpp
echo 1 | sudo tee /proc/sys/kernel/sched_schedstats
perf record \
--event sched:sched_stat_sleep \
--event sched:sched_process_exit \
--event sched:sched_switch --call-graph=dwarf \
--output perf.data.raw \
./a.out
echo 0 | sudo tee /proc/sys/kernel/sched_schedstats
perf inject --sched-stat --input perf.data.raw --output perf.data
~~~~~~~~~~~~~~~
Before this patch, the report clearly shows the off-by-one issue.
Most notably, the last sleep invocation is incorrectly attributed
to the "return 0;" line:
~~~~~~~~~~~~~~~
Overhead Source:Line
........ ...........
100.00% core.c:0
|
---__schedule core.c:0
schedule
do_nanosleep hrtimer.c:0
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath .tmp_entry_64.o:0
__nanosleep_nocancel .:0
std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > thread:323
|
|--90.08%--main test.cpp:9
| __libc_start_main
| _start
|
|--9.01%--main test.cpp:10
| __libc_start_main
| _start
|
--0.91%--main test.cpp:13
__libc_start_main
_start
~~~~~~~~~~~~~~~
With this patch here applied, the issue is fixed. The report becomes
much more usable:
~~~~~~~~~~~~~~~
Overhead Source:Line
........ ...........
100.00% core.c:0
|
---__schedule core.c:0
schedule
do_nanosleep hrtimer.c:0
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath .tmp_entry_64.o:0
__nanosleep_nocancel .:0
std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > thread:323
|
|--90.08%--main test.cpp:8
| __libc_start_main
| _start
|
|--9.01%--main test.cpp:9
| __libc_start_main
| _start
|
--0.91%--main test.cpp:10
__libc_start_main
_start
~~~~~~~~~~~~~~~
Similarly it works for signal frames:
~~~~~~~~~~~~~~~
__noinline void bar(void)
{
volatile long cnt = 0;
for (cnt = 0; cnt < 100000000; cnt++);
}
__noinline void foo(void)
{
bar();
}
void sig_handler(int sig)
{
foo();
}
int main(void)
{
signal(SIGUSR1, sig_handler);
raise(SIGUSR1);
foo();
return 0;
}
~~~~~~~~~~~~~~~~
Before, the report wrongly points to `signal.c:29` after raise():
~~~~~~~~~~~~~~~~
$ perf report --stdio --no-children -g srcline -s srcline
...
100.00% signal.c:11
|
---bar signal.c:11
|
|--50.49%--main signal.c:29
| __libc_start_main
| _start
|
--49.51%--0x33a8f
raise .:0
main signal.c:29
__libc_start_main
_start
~~~~~~~~~~~~~~~~
With this patch in, the issue is fixed and we instead get:
~~~~~~~~~~~~~~~~
100.00% signal signal [.] bar
|
---bar signal.c:11
|
|--50.49%--main signal.c:29
| __libc_start_main
| _start
|
--49.51%--0x33a8f
raise .:0
main signal.c:27
__libc_start_main
_start
~~~~~~~~~~~~~~~~
Note how this patch fixes this issue for both unwinding methods, i.e.
both dwfl and libunwind. The former case is straight-forward thanks
to dwfl_frame_pc(). For libunwind, we replace the functionality via
unw_is_signal_frame() for any but the very first frame.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yao Jin <yao.jin@linux.intel.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170524062129.32529-4-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-24 06:21:25 +00:00
|
|
|
if (!dwfl_frame_pc(state, &pc, &isactivation)) {
|
2014-02-19 15:52:57 +00:00
|
|
|
pr_err("%s", dwfl_errmsg(-1));
|
|
|
|
return DWARF_CB_ABORT;
|
|
|
|
}
|
|
|
|
|
perf report: Fix off-by-one for non-activation frames
As the documentation for dwfl_frame_pc says, frames that
are no activation frames need to have their program counter
decremented by one to properly find the function of the caller.
This fixes many cases where perf report currently attributes
the cost to the next line. I.e. I have code like this:
~~~~~~~~~~~~~~~
#include <thread>
#include <chrono>
using namespace std;
int main()
{
this_thread::sleep_for(chrono::milliseconds(1000));
this_thread::sleep_for(chrono::milliseconds(100));
this_thread::sleep_for(chrono::milliseconds(10));
return 0;
}
~~~~~~~~~~~~~~~
Now compile and record it:
~~~~~~~~~~~~~~~
g++ -std=c++11 -g -O2 test.cpp
echo 1 | sudo tee /proc/sys/kernel/sched_schedstats
perf record \
--event sched:sched_stat_sleep \
--event sched:sched_process_exit \
--event sched:sched_switch --call-graph=dwarf \
--output perf.data.raw \
./a.out
echo 0 | sudo tee /proc/sys/kernel/sched_schedstats
perf inject --sched-stat --input perf.data.raw --output perf.data
~~~~~~~~~~~~~~~
Before this patch, the report clearly shows the off-by-one issue.
Most notably, the last sleep invocation is incorrectly attributed
to the "return 0;" line:
~~~~~~~~~~~~~~~
Overhead Source:Line
........ ...........
100.00% core.c:0
|
---__schedule core.c:0
schedule
do_nanosleep hrtimer.c:0
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath .tmp_entry_64.o:0
__nanosleep_nocancel .:0
std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > thread:323
|
|--90.08%--main test.cpp:9
| __libc_start_main
| _start
|
|--9.01%--main test.cpp:10
| __libc_start_main
| _start
|
--0.91%--main test.cpp:13
__libc_start_main
_start
~~~~~~~~~~~~~~~
With this patch here applied, the issue is fixed. The report becomes
much more usable:
~~~~~~~~~~~~~~~
Overhead Source:Line
........ ...........
100.00% core.c:0
|
---__schedule core.c:0
schedule
do_nanosleep hrtimer.c:0
hrtimer_nanosleep
sys_nanosleep
entry_SYSCALL_64_fastpath .tmp_entry_64.o:0
__nanosleep_nocancel .:0
std::this_thread::sleep_for<long, std::ratio<1l, 1000l> > thread:323
|
|--90.08%--main test.cpp:8
| __libc_start_main
| _start
|
|--9.01%--main test.cpp:9
| __libc_start_main
| _start
|
--0.91%--main test.cpp:10
__libc_start_main
_start
~~~~~~~~~~~~~~~
Similarly it works for signal frames:
~~~~~~~~~~~~~~~
__noinline void bar(void)
{
volatile long cnt = 0;
for (cnt = 0; cnt < 100000000; cnt++);
}
__noinline void foo(void)
{
bar();
}
void sig_handler(int sig)
{
foo();
}
int main(void)
{
signal(SIGUSR1, sig_handler);
raise(SIGUSR1);
foo();
return 0;
}
~~~~~~~~~~~~~~~~
Before, the report wrongly points to `signal.c:29` after raise():
~~~~~~~~~~~~~~~~
$ perf report --stdio --no-children -g srcline -s srcline
...
100.00% signal.c:11
|
---bar signal.c:11
|
|--50.49%--main signal.c:29
| __libc_start_main
| _start
|
--49.51%--0x33a8f
raise .:0
main signal.c:29
__libc_start_main
_start
~~~~~~~~~~~~~~~~
With this patch in, the issue is fixed and we instead get:
~~~~~~~~~~~~~~~~
100.00% signal signal [.] bar
|
---bar signal.c:11
|
|--50.49%--main signal.c:29
| __libc_start_main
| _start
|
--49.51%--0x33a8f
raise .:0
main signal.c:27
__libc_start_main
_start
~~~~~~~~~~~~~~~~
Note how this patch fixes this issue for both unwinding methods, i.e.
both dwfl and libunwind. The former case is straight-forward thanks
to dwfl_frame_pc(). For libunwind, we replace the functionality via
unw_is_signal_frame() for any but the very first frame.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yao Jin <yao.jin@linux.intel.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170524062129.32529-4-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-24 06:21:25 +00:00
|
|
|
if (!isactivation)
|
|
|
|
--pc;
|
|
|
|
|
2014-02-19 15:52:57 +00:00
|
|
|
return entry(pc, ui) || !(--ui->max_stack) ?
|
|
|
|
DWARF_CB_ABORT : DWARF_CB_OK;
|
|
|
|
}
|
|
|
|
|
|
|
|
int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
|
2014-10-23 19:42:19 +00:00
|
|
|
struct thread *thread,
|
2014-02-19 15:52:57 +00:00
|
|
|
struct perf_sample *data,
|
|
|
|
int max_stack)
|
|
|
|
{
|
2015-11-19 13:01:19 +00:00
|
|
|
struct unwind_info *ui, ui_buf = {
|
2014-02-19 15:52:57 +00:00
|
|
|
.sample = data,
|
|
|
|
.thread = thread,
|
2014-10-23 19:42:19 +00:00
|
|
|
.machine = thread->mg->machine,
|
2014-02-19 15:52:57 +00:00
|
|
|
.cb = cb,
|
|
|
|
.arg = arg,
|
|
|
|
.max_stack = max_stack,
|
|
|
|
};
|
|
|
|
Dwarf_Word ip;
|
2015-11-19 13:01:19 +00:00
|
|
|
int err = -EINVAL, i;
|
2014-02-19 15:52:57 +00:00
|
|
|
|
|
|
|
if (!data->user_regs.regs)
|
|
|
|
return -EINVAL;
|
|
|
|
|
2015-11-19 13:01:19 +00:00
|
|
|
ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack);
|
|
|
|
if (!ui)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
*ui = ui_buf;
|
|
|
|
|
|
|
|
ui->dwfl = dwfl_begin(&offline_callbacks);
|
|
|
|
if (!ui->dwfl)
|
2014-02-19 15:52:57 +00:00
|
|
|
goto out;
|
|
|
|
|
|
|
|
err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP);
|
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
|
2015-11-19 13:01:19 +00:00
|
|
|
err = report_module(ip, ui);
|
2014-02-19 15:52:57 +00:00
|
|
|
if (err)
|
|
|
|
goto out;
|
|
|
|
|
2018-03-18 17:50:53 +00:00
|
|
|
err = !dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui);
|
|
|
|
if (err)
|
2014-02-19 15:52:57 +00:00
|
|
|
goto out;
|
|
|
|
|
2015-11-19 13:01:19 +00:00
|
|
|
err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui);
|
2014-02-19 15:52:57 +00:00
|
|
|
|
2017-06-01 21:00:21 +00:00
|
|
|
if (err && ui->max_stack != max_stack)
|
2014-02-19 15:52:57 +00:00
|
|
|
err = 0;
|
|
|
|
|
2015-11-19 13:01:19 +00:00
|
|
|
/*
|
|
|
|
* Display what we got based on the order setup.
|
|
|
|
*/
|
|
|
|
for (i = 0; i < ui->idx && !err; i++) {
|
|
|
|
int j = i;
|
|
|
|
|
|
|
|
if (callchain_param.order == ORDER_CALLER)
|
|
|
|
j = ui->idx - i - 1;
|
|
|
|
|
|
|
|
err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0;
|
|
|
|
}
|
|
|
|
|
2014-02-19 15:52:57 +00:00
|
|
|
out:
|
|
|
|
if (err)
|
|
|
|
pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));
|
|
|
|
|
2015-11-19 13:01:19 +00:00
|
|
|
dwfl_end(ui->dwfl);
|
|
|
|
free(ui);
|
2014-02-19 15:52:57 +00:00
|
|
|
return 0;
|
|
|
|
}
|