'DWARF unwind' 'perf test' can sometimes fail:
$ perf test -v 74
Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
74: Test dwarf unwind :
--- start ---
test child forked, pid 3785254
Problems creating module maps, continuing anyway...
Problems creating module maps, continuing anyway...
unwind: test__arch_unwind_sample:ip = 0x102d0ad4c (0x36ad4c)
unwind: access_mem addr 0x7fffc33128c8, val 1031c3228, offset 120
unwind: access_mem addr 0x7fffc33128d0, val 12427cc70, offset 128
<snip>
unwind: test_dwarf_unwind__krava_3:ip = 0x102b8768b (0x1e768b)
unwind: access_mem addr 0x7fffc3313048, val 7fffc3313050, offset 2040
unwind: access_mem addr 0x7fffc3313060, val 102b8777c, offset 2064
unwind: test_dwarf_unwind__krava_2:ip = 0x102b8770b (0x1e770b)
unwind: access_mem addr 0x7fffc3313088, val 7fffc3313090, offset 2104
unwind: access_mem addr 0x7fffc33130a0, val 102b87890, offset 2128
unwind: test_dwarf_unwind__krava_1:ip = 0x102b8777b (0x1e777b)
unwind: access_mem addr 0x7fffc3313108, val 10323a274, offset 2232
unwind: access_mem addr 0x7fffc3313110, val ffffffffffffffff, offset 2240
unwind: access_mem addr 0x7fffc3313118, val 102c08ed0, offset 2248
unwind: access_mem addr 0x7fffc3313120, val 1031db000, offset 2256
unwind: access_mem addr 0x7fffc3313128, val 7fffc3313130, offset 2264
unwind: access_mem addr 0x7fffc3313140, val 102b45ee8, offset 2288
unwind: '':ip = 0x102b8788f (0x1e788f)
failed: got unresolved address 0x102b8788f
unwind: failed with 'no error'
got wrong number of stack entries 0 != 8
test child finished with -1
---- end ----
Test dwarf unwind: FAILED!
We expect to resolve test__dwarf_unwind as the last symbol, but that
function can be optimized away:
$ objdump -tT /usr/bin/perf | grep dwarf_unwind
000000000083b018 g DO .data 0000000000000040 Base tests__dwarf_unwind
00000000001e7750 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_1
00000000001e76e0 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_2
00000000001e7620 g DF .text 00000000000000b4 Base 0x60 test_dwarf_unwind__krava_3
00000000001e74f0 g DF .text 0000000000000128 Base 0x60 test_dwarf_unwind__compare
00000000001e7350 g DF .text 000000000000019c Base 0x60 test_dwarf_unwind__thread
000000000083b000 g DO .data 0000000000000018 Base suite__dwarf_unwind
Fix this similar to commit fdf7c49c20 ("perf tests: Fix dwarf
unwind for stripped binaries") by marking the function as a global and
adding the 'noinline' attribute to it.
With this patch:
$ objdump -tT perf | grep dwarf_unwind
000000000083b018 g DO .data 0000000000000040 Base tests__dwarf_unwind
00000000001e80f0 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_1
00000000001e8080 g DF .text 0000000000000068 Base 0x60 test_dwarf_unwind__krava_2
00000000001e7fc0 g DF .text 00000000000000b4 Base 0x60 test_dwarf_unwind__krava_3
00000000001e7e90 g DF .text 0000000000000128 Base 0x60 test_dwarf_unwind__compare
00000000001e7cf0 g DF .text 000000000000019c Base 0x60 test_dwarf_unwind__thread
00000000001e8160 g DF .text 0000000000000248 Base 0x60 test__dwarf_unwind
000000000083b000 g DO .data 0000000000000018 Base suite__dwarf_unwind
$ ./perf test 74
74: Test dwarf unwind : Ok
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20230125123442.107156-1-naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Commit Fixes: b9f6fbb3b2 ("perf arm64: Inject missing frames when
using 'perf record --call-graph=fp'") intended to add a 'best effort'
DWARF unwind that improved the frame pointer stack in most scenarios.
It's expected that the unwind will fail sometimes, but this shouldn't be
reported as an error. It only works when the return address can be
determined from the contents of the link register alone.
Fix the error shown when the unwinder requires extra registers by adding
a new flag that suppresses error messages. This flag is not set in the
normal --call-graph=dwarf unwind mode so that behavior is not changed.
Fixes: b9f6fbb3b2 ("perf arm64: Inject missing frames when using 'perf record --call-graph=fp'")
Reported-by: John Garry <john.garry@huawei.com>
Signed-off-by: James Clark <james.clark@arm.com>
Tested-by: John Garry <john.garry@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexandre Truong <alexandre.truong@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220406145651.1392529-1-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In places where the equivalent was already being done, i.e.:
free(a);
a = NULL;
And in placs where struct members are being freed so that if we have
some erroneous reference to its struct, then accesses to freed members
will result in segfaults, which we can detect faster than use after free
to areas that may still have something seemingly valid.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-jatyoofo5boc1bsvoig6bb6i@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When we strip the perf binary, dwarf unwind test stop
to work. The reason is that strip will remove static
function symbols, which we need to check for unwind.
This change will keep this test working in cases where
the global symbols are put into dynamic symbol table,
which is the case on x86. It still won't work on powerpc.
Making those 5 local functions global, and adding
'test_dwarf_unwind__' to their names.
Committer testing:
Before:
# perf test dwarf
58: DWARF unwind : Ok
# strip ~/bin/perf
# perf test dwarf
58: DWARF unwind : FAILED!
# perf test -v dwarf
58: DWARF unwind :
--- start ---
test child forked, pid 6590
unwind: thread map already set, dso=/home/acme/bin/perf
<SNIP>
unwind: access_mem addr 0x7ffce6c48098 val 48563f, offset 1144
unwind: test__dwarf_unwind:ip = 0x4a54e5 (0xa54e5)
got: test__dwarf_unwind 0xa54e5, expecting test__dwarf_unwind
unwind: '':ip = 0x4a50bb (0xa50bb)
failed: got unresolved address 0xa50bb
unwind failed
test child finished with -1
---- end ----
DWARF unwind: FAILED!
#
After:
# perf test dwarf
58: DWARF unwind : Ok
# strip ~/bin/perf
# perf test dwarf
58: DWARF unwind : Ok
#
# perf test -v dwarf
58: DWARF unwind :
--- start ---
test child forked, pid 7219
unwind: thread map already set, dso=/home/acme/bin/perf
<SNIP>
unwind: access_mem addr 0x7fff007da2c8 val 48575f, offset 1144
unwind: test__arch_unwind_sample:ip = 0x589044 (0x189044)
got: test__arch_unwind_sample 0x189044, expecting test__arch_unwind_sample
unwind: test_dwarf_unwind__thread:ip = 0x4a52f7 (0xa52f7)
got: test_dwarf_unwind__thread 0xa52f7, expecting test_dwarf_unwind__thread
unwind: test_dwarf_unwind__compare:ip = 0x4a5468 (0xa5468)
got: test_dwarf_unwind__compare 0xa5468, expecting test_dwarf_unwind__compare
unwind: bsearch:ip = 0x7f6608ae94d8 (0x394d8)
got: bsearch 0x394d8, expecting bsearch
unwind: test_dwarf_unwind__krava_3:ip = 0x4a54d1 (0xa54d1)
got: test_dwarf_unwind__krava_3 0xa54d1, expecting test_dwarf_unwind__krava_3
unwind: test_dwarf_unwind__krava_2:ip = 0x4a550b (0xa550b)
got: test_dwarf_unwind__krava_2 0xa550b, expecting test_dwarf_unwind__krava_2
unwind: test_dwarf_unwind__krava_1:ip = 0x4a554b (0xa554b)
got: test_dwarf_unwind__krava_1 0xa554b, expecting test_dwarf_unwind__krava_1
unwind: test__dwarf_unwind:ip = 0x4a5605 (0xa5605)
got: test__dwarf_unwind 0xa5605, expecting test__dwarf_unwind
test child finished with 0
---- end ----
DWARF unwind: Ok
#
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180206181813.10943-17-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When setting up DWARF callchains on specific events, without using
'record' or 'trace' --call-graph, but instead doing it like:
perf trace -e cycles/call-graph=dwarf/
The unwind__prepare_access() call in thread__insert_map() when we
process PERF_RECORD_MMAP(2) metadata events were not being performed,
precluding us from using per-event DWARF callchains, handling them just
when we asked for all events to be DWARF, using "--call-graph dwarf".
We do it in the PERF_RECORD_MMAP because we have to look at one of the
executable maps to figure out the executable type (64-bit, 32-bit) of
the DSO laid out in that mmap. Also to look at the architecture where
the perf.data file was recorded.
All this probably should be deferred to when we process a sample for
some thread that has callchains, so that we do this processing only for
the threads with samples, not for all of them.
For now, fix using DWARF on specific events.
Before:
# perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.048 ms
--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.048/0.048/0.048/0.000 ms
0.000 probe_libc:inet_pton:(7fe9597bb350))
Problem processing probe_libc:inet_pton callchain, skipping...
#
After:
# perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.060 ms
--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.060/0.060/0.060/0.000 ms
0.000 probe_libc:inet_pton:(7fd4aa930350))
__inet_pton (inlined)
gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so)
__GI_getaddrinfo (inlined)
[0xffffaa804e51af3f] (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
[0xffffaa804e51b379] (/usr/bin/ping)
#
# perf trace --call-graph=dwarf --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.057 ms
--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.057/0.057/0.057/0.000 ms
0.000 probe_libc:inet_pton:(7f9363b9e350))
__inet_pton (inlined)
gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so)
__GI_getaddrinfo (inlined)
[0xffffa9e8a14e0f3f] (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
[0xffffa9e8a14e1379] (/usr/bin/ping)
#
# perf trace --call-graph=fp --no-syscalls -e probe_libc:inet_pton/call-graph=dwarf/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.077 ms
--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.077/0.077/0.077/0.000 ms
0.000 probe_libc:inet_pton:(7f4947e1c350))
__inet_pton (inlined)
gaih_inet.constprop.7 (/usr/lib64/libc-2.26.so)
__GI_getaddrinfo (inlined)
[0xffffaa716d88ef3f] (/usr/bin/ping)
__libc_start_main (/usr/lib64/libc-2.26.so)
[0xffffaa716d88f379] (/usr/bin/ping)
#
# perf trace --no-syscalls -e probe_libc:inet_pton/call-graph=fp/ ping -6 -c 1 ::1
PING ::1(::1) 56 data bytes
64 bytes from ::1: icmp_seq=1 ttl=64 time=0.078 ms
--- ::1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.078/0.078/0.078/0.000 ms
0.000 probe_libc:inet_pton:(7fa157696350))
__GI___inet_pton (/usr/lib64/libc-2.26.so)
getaddrinfo (/usr/lib64/libc-2.26.so)
[0xffffa9ba39c74f40] (/usr/bin/ping)
#
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Hendrick Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/r/20180116182650.GE16107@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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>
When cross compiling perf and I want to link against a self-compiled
libunwind, I usually make the custom path where the libunwind headers
exist visible by adding the libunwind prefix to the include path when
compiling perf, i.e.:
~~~~~
$ ls $HOME/projects/compiled/other/include/
libunwind-coredump.h libunwind.h libunwind-x86_64.h
libunwind-common.h libunwind-dynamic.h libunwind-ptrace.h
unwind.h
$ make EXTRA_CFLAGS="-I$HOME/projects/compiled/other/include/
~~~~~~
Note the `unwind.h` header from libunwind which leads to compile
errors when compiling tests/dwarf-unwind.c, since it shadows perf's
util/unwind.h:
~~~~~
tests/dwarf-unwind.c:41:32: error: ‘struct unwind_entry’ declared inside parameter list will not be visible outside of this definition or declaration [-Werror]
static int unwind_entry(struct unwind_entry *entry, void *arg)
^~~~~~~~~~~~
tests/dwarf-unwind.c: In function ‘unwind_entry’:
tests/dwarf-unwind.c:44:22: error: dereferencing pointer to incomplete type ‘struct unwind_entry’
char *symbol = entry->sym ? entry->sym->name : NULL;
^~
tests/dwarf-unwind.c: In function ‘unwind_thread’:
tests/dwarf-unwind.c:92:8: error: implicit declaration of function ‘unwind__get_entries’; did you mean ‘unwind_entry’? [-Werror=implicit-function-declaration]
err = unwind__get_entries(unwind_entry, &cnt, thread,
^~~~~~~~~~~~~~~~~~~
unwind_entry
tests/dwarf-unwind.c:92:8: error: nested extern declaration of ‘unwind__get_entries’ [-Werror=nested-externs]
~~~~~~
Fix this compile error by specificing an explicit include of perf's
unwind.h in the util folder.
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/20170906150209.12579-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Some tests have sub-tests we want to run, so allow passing this.
Wang tried to avoid having to touch all tests, but then, having the
test.func in an anonymous union makes the build fail on older compilers,
like the one in RHEL6, where:
test a = {
.func = foo,
};
fails.
To fix it leave the func pointer in the main structure and pass the subtest
index to all tests, end result function is the same, but we have just one
function pointer, not two, with and without the subtest index as an argument.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-5genj0ficwdmelpoqlds0u4y@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In addition to using refcounts for the struct thread lifetime
management, we need to protect access to machine->threads from
concurrent access.
That happens in 'perf top', where a thread processes events, inserting
and deleting entries from that rb_tree while another thread decays
hist_entries, that end up dropping references and ultimately deleting
threads from the rb_tree and releasing its resources when no further
hist_entry (or other data structures, like in 'perf sched') references
it.
So the rule is the same for refcounts + protected trees in the kernel,
get the tree lock, find object, bump the refcount, drop the tree lock,
return, use object, drop the refcount if no more use of it is needed,
keep it if storing it in some other data structure, drop when releasing
that data structure.
I.e. pair "t = machine__find(new)_thread()" with a "thread__put(t)", and
"perf_event__preprocess_sample(&al)" with "addr_location__put(&al)".
The addr_location__put() one is because as we return references to
several data structures, we may end up adding more reference counting
for the other data structures and then we'll drop it at
addr_location__put() time.
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-bs9rt4n0jw3hi9f3zxyy3xln@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Perf tool fails to unwind user stack if the event raises in a shared
object. This patch improves tests/dwarf-unwind.c to demonstrate the
problem by utilizing commonly used glibc function "bsearch". If perf is
not statically linked, the testcase will try to unwind a mixed call
trace.
By debugging libunwind I found that there is a bug in unwind-libunwind:
it always passes 0 as segbase to libunwind, cause libunwind unable to
locate debug_frame entry fir first level ip address (I add some more
debugging output into libunwind to make things clear):
>_Uarm_dwarf_find_debug_frame: start_ip = 10be98, end_ip = 10c2a4
>_Uarm_dwarf_find_debug_frame: found debug_frame table `/lib/libc-2.18.so': segbase=0x0, len=7, gp=0x0, table_data=0x449388
>_Uarm_dwarf_search_unwind_table: call lookup:ip = b6cd3bcc, segbase = 0, rel_ip = b6cd3bcc
>lookup: e->start_ip_offset = bcf18 (rel_ip = b6cd3bcc)
>lookup: e->start_ip_offset = 6d314 (rel_ip = b6cd3bcc)
>lookup: e->start_ip_offset = 33d0c (rel_ip = b6cd3bcc)
...
>lookup: e->start_ip_offset = 15d0c (rel_ip = b6cd3bcc)
>lookup: e->start_ip_offset = 15c40 (rel_ip = b6cd3bcc)
>_Uarm_dwarf_search_unwind_table: IP b6cd3bcc inside range b6c12000-b6d4c000, but no explicit unwind info found
>put_rs_cache: unmasking signals/interrupts and releasing lock
>_Uarm_dwarf_step: returning -10
>_Uarm_step: dwarf_step()=-10
This patch passes map->start as segbase to dwarf_find_debug_frame(), so
di will be initialized correctly.
In addition, dso and executable are different when setting segbase. This
patch first check whether the elf is executable, and pass segbase only
for shared object.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1421203007-75799-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
