Michael reported the segfault when kernel.kptr_restrict=2 is set. $ perf record ls ... perf: Segmentation fault Obtained 16 stack frames. ./perf(dump_stack+0x2d) [0x5068df] ./perf(sighandler_dump_stack+0x2d) [0x5069bf] ./perf() [0x43e47b] /lib64/libc.so.6(+0x3594f) [0x7f762004794f] /lib64/libc.so.6(strlen+0x26) [0x7f762009ef86] /lib64/libc.so.6(__strdup+0xd) [0x7f762009ecbd] ./perf(maps__set_kallsyms_ref_reloc_sym+0x4d) [0x51590f] ./perf(machine__create_kernel_maps+0x136) [0x50a7de] ./perf(perf_session__create_kernel_maps+0x2c) [0x510a81] ./perf(perf_session__new+0x13d) [0x510e23] ./perf() [0x43fd61] ./perf(cmd_record+0x704) [0x441823] ./perf() [0x4bc1a0] ./perf() [0x4bc40d] ./perf() [0x4bc55f] ./perf(main+0x2d5) [0x4bc939] Segmentation fault (core dumped) The reason is that with kernel.kptr_restrict=2, we don't get the symbol from machine__get_running_kernel_start, which we want to use in maps__set_kallsyms_ref_reloc_sym and we crash. Check the symbol name value before calling maps__set_kallsyms_ref_reloc_sym() and succeed without ref_reloc_sym being set. It's safe because we check its existence before we use it. Reported-by: Michael Petlan <mpetlan@redhat.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20170626095153.553-1-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In commit 613f050d68a8 ("perf probe: Fix to probe on gcc generated
functions in modules"), the offset from symbol is, incorrectly, added
to the trace point address. This leads to incorrect probe trace points
for inlined functions and when using relative line number on symbols.
Prior this patch:
$ perf probe -m nf_nat -D in_range
p:probe/in_range nf_nat:in_range.isra.9+0
$ perf probe -m i40e -D i40e_clean_rx_irq
p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2212
$ perf probe -m i40e -D i40e_clean_rx_irq:16
p:probe/i40e_clean_rx_irq i40e:i40e_lan_xmit_frame+626
After:
$ perf probe -m nf_nat -D in_range
p:probe/in_range nf_nat:in_range.isra.9+0
$ perf probe -m i40e -D i40e_clean_rx_irq
p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+1106
$ perf probe -m i40e -D i40e_clean_rx_irq:16
p:probe/i40e_clean_rx_irq i40e:i40e_napi_poll+2665
Committer testing:
Using 'pfunct', a tool found in the 'dwarves' package [1], one can ask what are
the functions that while not being explicitely marked as inline, were inlined
by the compiler:
# pfunct --cc_inlined /lib/modules/4.12.0-rc4+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko | head
__ew32
e1000_regdump
e1000e_dump_ps_pages
e1000_desc_unused
e1000e_systim_to_hwtstamp
e1000e_rx_hwtstamp
e1000e_update_rdt_wa
e1000e_update_tdt_wa
e1000_put_txbuf
e1000_consume_page
Then ask 'perf probe' to produce the kprobe_tracer probe definitions for two of
them:
# perf probe -m e1000e -D e1000e_rx_hwtstamp
p:probe/e1000e_rx_hwtstamp e1000e:e1000_receive_skb+74
# perf probe -m e1000e -D e1000_consume_page
p:probe/e1000_consume_page e1000e:e1000_clean_jumbo_rx_irq+876
p:probe/e1000_consume_page_1 e1000e:e1000_clean_jumbo_rx_irq+1506
p:probe/e1000_consume_page_2 e1000e:e1000_clean_rx_irq_ps+1074
Now lets concentrate on the 'e1000_consume_page' one, that was inlined twice in
e1000_clean_jumbo_rx_irq(), lets see what readelf says about the DWARF tags for
that function:
$ readelf -wi /lib/modules/4.12.0-rc4+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko
<SNIP>
<1><13e27b>: Abbrev Number: 121 (DW_TAG_subprogram)
<13e27c> DW_AT_name : (indirect string, offset: 0xa8945): e1000_clean_jumbo_rx_irq
<13e287> DW_AT_low_pc : 0x17a30
<3><13e6ef>: Abbrev Number: 119 (DW_TAG_inlined_subroutine)
<13e6f0> DW_AT_abstract_origin: <0x13ed2c>
<13e6f4> DW_AT_low_pc : 0x17be6
<SNIP>
<1><13ed2c>: Abbrev Number: 142 (DW_TAG_subprogram)
<13ed2e> DW_AT_name : (indirect string, offset: 0xa54c3): e1000_consume_page
So, the first time in e1000_clean_jumbo_rx_irq() where e1000_consume_page() is
inlined is at PC 0x17be6, which subtracted from e1000_clean_jumbo_rx_irq()'s
address, gives us the offset we should use in the probe definition:
0x17be6 - 0x17a30 = 438
but above we have 876, which is twice as much.
Lets see the second inline expansion of e1000_consume_page() in
e1000_clean_jumbo_rx_irq():
<3><13e86e>: Abbrev Number: 119 (DW_TAG_inlined_subroutine)
<13e86f> DW_AT_abstract_origin: <0x13ed2c>
<13e873> DW_AT_low_pc : 0x17d21
0x17d21 - 0x17a30 = 753
So we where adding it at twice the offset from the containing function as we
should.
And then after this patch:
# perf probe -m e1000e -D e1000e_rx_hwtstamp
p:probe/e1000e_rx_hwtstamp e1000e:e1000_receive_skb+37
# perf probe -m e1000e -D e1000_consume_page
p:probe/e1000_consume_page e1000e:e1000_clean_jumbo_rx_irq+438
p:probe/e1000_consume_page_1 e1000e:e1000_clean_jumbo_rx_irq+753
p:probe/e1000_consume_page_2 e1000e:e1000_clean_jumbo_rx_irq+1353
#
Which matches the two first expansions and shows that because we were
doubling the offset it would spill over the next function:
readelf -sw /lib/modules/4.12.0-rc4+/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko
673: 0000000000017a30 1626 FUNC LOCAL DEFAULT 2 e1000_clean_jumbo_rx_irq
674: 0000000000018090 2013 FUNC LOCAL DEFAULT 2 e1000_clean_rx_irq_ps
This is the 3rd inline expansion of e1000_consume_page() in
e1000_clean_jumbo_rx_irq():
<3><13ec77>: Abbrev Number: 119 (DW_TAG_inlined_subroutine)
<13ec78> DW_AT_abstract_origin: <0x13ed2c>
<13ec7c> DW_AT_low_pc : 0x17f79
0x17f79 - 0x17a30 = 1353
So:
0x17a30 + 2 * 1353 = 0x184c2
And:
0x184c2 - 0x18090 = 1074
Which explains the bogus third expansion for e1000_consume_page() to end up at:
p:probe/e1000_consume_page_2 e1000e:e1000_clean_rx_irq_ps+1074
All fixed now :-)
[1] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 613f050d68a8 ("perf probe: Fix to probe on gcc generated functions in modules")
Link: http://lkml.kernel.org/r/20170621164134.5701-1-bjorn.topel@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The PC returned by dwfl_frame_pc() may map into a not-yet-reported module. We have to report it before we continue unwinding. But when we query for the isactivation flag in dwfl_frame_pc, libdw will actually do one more unwinding step internally which can then break and lead to missed frames or broken stacks. With libunwind we get e.g.: ~~~~~ heaptrack_gui 2228 135073.400474: 613969 cycles: 108c8e [unknown] (/usr/lib/libQt5Core.so.5.8.0) 1093bc [unknown] (/usr/lib/libQt5Core.so.5.8.0) 109e7b QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) 1470ff [unknown] (/usr/lib/libQt5Core.so.5.8.0) 147f67 QSystemLocale::query (/usr/lib/libQt5Core.so.5.8.0) 109fbf QLocalePrivate::updateSystemPrivate (/usr/lib/libQt5Core.so.5.8.0) 10aa27 QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) 1e02c3 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 2113bb [unknown] (/usr/lib/libQt5Core.so.5.8.0) 211505 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 1b5df0 QFileInfo::exists (/usr/lib/libQt5Core.so.5.8.0) 92eb2 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 93423 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 93d2a QLibraryInfo::location (/usr/lib/libQt5Core.so.5.8.0) 2170af [unknown] (/usr/lib/libQt5Core.so.5.8.0) 297c53 QCoreApplicationPrivate::init (/usr/lib/libQt5Core.so.5.8.0) f7cde QGuiApplicationPrivate::init (/usr/lib/libQt5Gui.so.5.8.0) 1589e8 QApplicationPrivate::init (/usr/lib/libQt5Widgets.so.5.8.0) 78622 main (/home/milian/projects/compiled/other/bin/heaptrack_gui) 20439 __libc_start_main (/usr/lib/libc-2.25.so) 78299 _start (/home/milian/projects/compiled/other/bin/heaptrack_gui) heaptrack_gui 2228 135073.401156: 569521 cycles: 131633 QString::endsWith (/usr/lib/libQt5Core.so.5.8.0) 1a0701 QDir::cleanPath (/usr/lib/libQt5Core.so.5.8.0) 21b82d [unknown] (/usr/lib/libQt5Core.so.5.8.0) 1b3727 QFileInfo::canonicalFilePath (/usr/lib/libQt5Core.so.5.8.0) 2780c7 QFactoryLoader::update (/usr/lib/libQt5Core.so.5.8.0) 279525 QFactoryLoader::QFactoryLoader (/usr/lib/libQt5Core.so.5.8.0) e5bd0 QPlatformIntegrationFactory::create (/usr/lib/libQt5Gui.so.5.8.0) f5a1c QGuiApplicationPrivate::createPlatformIntegration (/usr/lib/libQt5Gui.so.5.8.0) f650c QGuiApplicationPrivate::createEventDispatcher (/usr/lib/libQt5Gui.so.5.8.0) 298524 QCoreApplicationPrivate::init (/usr/lib/libQt5Core.so.5.8.0) f7cde QGuiApplicationPrivate::init (/usr/lib/libQt5Gui.so.5.8.0) 1589e8 QApplicationPrivate::init (/usr/lib/libQt5Widgets.so.5.8.0) 78622 main (/home/milian/projects/compiled/other/bin/heaptrack_gui) 20439 __libc_start_main (/usr/lib/libc-2.25.so) 78299 _start (/home/milian/projects/compiled/other/bin/heaptrack_gui) ~~~~~ Note the two frames 1589e8 and 78622 in the first sample. These are missing when unwinding with libdw. The second sample's breakage is more obvious: ~~~~~ heaptrack_gui 2228 135073.400474: 613969 cycles: 108c8e [unknown] (/usr/lib/libQt5Core.so.5.8.0) 1093bc [unknown] (/usr/lib/libQt5Core.so.5.8.0) 109e7b QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) 1470ff [unknown] (/usr/lib/libQt5Core.so.5.8.0) 147f67 QSystemLocale::query (/usr/lib/libQt5Core.so.5.8.0) 109fbf QLocalePrivate::updateSystemPrivate (/usr/lib/libQt5Core.so.5.8.0) 10aa27 QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) 1e02c3 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 2113bb [unknown] (/usr/lib/libQt5Core.so.5.8.0) 211505 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 1b5df0 QFileInfo::exists (/usr/lib/libQt5Core.so.5.8.0) 92eb2 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 93423 [unknown] (/usr/lib/libQt5Core.so.5.8.0) 93d2a QLibraryInfo::location (/usr/lib/libQt5Core.so.5.8.0) 2170af [unknown] (/usr/lib/libQt5Core.so.5.8.0) 297c53 QCoreApplicationPrivate::init (/usr/lib/libQt5Core.so.5.8.0) f7cde QGuiApplicationPrivate::init (/usr/lib/libQt5Gui.so.5.8.0) 20439 __libc_start_main (/usr/lib/libc-2.25.so) 78299 _start (/home/milian/projects/compiled/other/bin/heaptrack_gui) heaptrack_gui 2228 135073.401156: 569521 cycles: 131633 QString::endsWith (/usr/lib/libQt5Core.so.5.8.0) 1a0701 QDir::cleanPath (/usr/lib/libQt5Core.so.5.8.0) 21b82d [unknown] (/usr/lib/libQt5Core.so.5.8.0) 1b3727 QFileInfo::canonicalFilePath (/usr/lib/libQt5Core.so.5.8.0) 2780c7 QFactoryLoader::update (/usr/lib/libQt5Core.so.5.8.0) 279525 QFactoryLoader::QFactoryLoader (/usr/lib/libQt5Core.so.5.8.0) e5bd0 QPlatformIntegrationFactory::create (/usr/lib/libQt5Gui.so.5.8.0) 723dbf [unknown] ([unknown]) ~~~~~ This patch fixes this issue and the libdw unwinder mimicks the libunwind behavior more closely. Signed-off-by: Milian Wolff <milian.wolff@kdab.com> Acked-by: Jan Kratochvil <jan.kratochvil@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/20170602143753.16907-2-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
With commit: 0a943cb10ce78 (tools build: Add HOSTARCH Makefile variable)
when building for ARCH=x86_64, ARCH=x86_64 is passed to perf instead of
ARCH=x86, so the perf build process searchs header files from
tools/arch/x86_64/include, which doesn't exist.
The following build failure is seen:
In file included from util/event.c:2:0:
tools/include/uapi/linux/mman.h:4:27: fatal error: uapi/asm/mman.h: No such file or directory
compilation terminated.
Fix this issue by using SRCARCH instead of ARCH in perf, just like the
main kernel Makefile and tools/objtool's.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Rui Teng <rui.teng@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 0a943cb10ce7 ("tools build: Add HOSTARCH Makefile variable")
Link: http://lkml.kernel.org/r/1491793357-14977-2-git-send-email-jiada_wang@mentor.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since commit 18e7a45af91a ("perf/x86: Reject non sampling events with
precise_ip") returns -EINVAL for sys_perf_event_open() with an attribute
with (attr.precise_ip > 0 && attr.sample_period == 0), just like is done
in the routine used to probe the max precise level when no events were
passed to 'perf record' or 'perf top', i.e.:
perf_evsel__new_cycles()
perf_event_attr__set_max_precise_ip()
The x86 code, in x86_pmu_hw_config(), which is called all the way from
sys_perf_event_open() did, starting with the aforementioned commit:
/* There's no sense in having PEBS for non sampling events: */
if (!is_sampling_event(event))
return -EINVAL;
Which makes it fail for cycles:ppp, cycles:pp and cycles:p, always using
just the non precise cycles variant.
To make sure that this is the case, I tested it, before this patch,
with:
# perf probe -L x86_pmu_hw_config
<x86_pmu_hw_config@/home/acme/git/linux/arch/x86/events/core.c:0>
0 int x86_pmu_hw_config(struct perf_event *event)
1 {
2 if (event->attr.precise_ip) {
<SNIP>
17 if (event->attr.precise_ip > precise)
18 return -EOPNOTSUPP;
/* There's no sense in having PEBS for non sampling events: */
21 if (!is_sampling_event(event))
22 return -EINVAL;
}
<SNIP>
# perf probe x86_pmu_hw_config:22
Added new events:
probe:x86_pmu_hw_config (on x86_pmu_hw_config:22)
probe:x86_pmu_hw_config_1 (on x86_pmu_hw_config:22)
You can now use it in all perf tools, such as:
perf record -e probe:x86_pmu_hw_config_1 -aR sleep 1
# perf trace -e perf_event_open,probe:x86_pmu_hwconfig*/max-stack=16/ perf record usleep 1
0.000 ( 0.015 ms): perf/4150 perf_event_open(attr_uptr: 0x7ffebc8ba110, cpu: -1, group_fd: -1 ) ...
0.015 ( ): probe:x86_pmu_hw_config:(ffffffff9c0065e1))
x86_pmu_hw_config ([kernel.kallsyms])
hsw_hw_config ([kernel.kallsyms])
x86_pmu_event_init ([kernel.kallsyms])
perf_try_init_event ([kernel.kallsyms])
perf_event_alloc ([kernel.kallsyms])
SYSC_perf_event_open ([kernel.kallsyms])
sys_perf_event_open ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
return_from_SYSCALL_64 ([kernel.kallsyms])
syscall (/usr/lib64/libc-2.24.so)
perf_event_attr__set_max_precise_ip (/home/acme/bin/perf)
perf_evsel__new_cycles (/home/acme/bin/perf)
perf_evlist__add_default (/home/acme/bin/perf)
cmd_record (/home/acme/bin/perf)
run_builtin (/home/acme/bin/perf)
handle_internal_command (/home/acme/bin/perf)
0.000 ( 0.021 ms): perf/4150 ... [continued]: perf_event_open()) = -1 EINVAL Invalid argument
0.023 ( 0.002 ms): perf/4150 perf_event_open(attr_uptr: 0x7ffebc8ba110, cpu: -1, group_fd: -1 ) ...
0.025 ( ): probe:x86_pmu_hw_config:(ffffffff9c0065e1))
x86_pmu_hw_config ([kernel.kallsyms])
hsw_hw_config ([kernel.kallsyms])
x86_pmu_event_init ([kernel.kallsyms])
perf_try_init_event ([kernel.kallsyms])
perf_event_alloc ([kernel.kallsyms])
SYSC_perf_event_open ([kernel.kallsyms])
sys_perf_event_open ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
return_from_SYSCALL_64 ([kernel.kallsyms])
syscall (/usr/lib64/libc-2.24.so)
perf_event_attr__set_max_precise_ip (/home/acme/bin/perf)
perf_evsel__new_cycles (/home/acme/bin/perf)
perf_evlist__add_default (/home/acme/bin/perf)
cmd_record (/home/acme/bin/perf)
run_builtin (/home/acme/bin/perf)
handle_internal_command (/home/acme/bin/perf)
0.023 ( 0.004 ms): perf/4150 ... [continued]: perf_event_open()) = -1 EINVAL Invalid argument
0.028 ( 0.002 ms): perf/4150 perf_event_open(attr_uptr: 0x7ffebc8ba110, cpu: -1, group_fd: -1 ) ...
0.030 ( ): probe:x86_pmu_hw_config:(ffffffff9c0065e1))
x86_pmu_hw_config ([kernel.kallsyms])
hsw_hw_config ([kernel.kallsyms])
x86_pmu_event_init ([kernel.kallsyms])
perf_try_init_event ([kernel.kallsyms])
perf_event_alloc ([kernel.kallsyms])
SYSC_perf_event_open ([kernel.kallsyms])
sys_perf_event_open ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
return_from_SYSCALL_64 ([kernel.kallsyms])
syscall (/usr/lib64/libc-2.24.so)
perf_event_attr__set_max_precise_ip (/home/acme/bin/perf)
perf_evsel__new_cycles (/home/acme/bin/perf)
perf_evlist__add_default (/home/acme/bin/perf)
cmd_record (/home/acme/bin/perf)
run_builtin (/home/acme/bin/perf)
handle_internal_command (/home/acme/bin/perf)
0.028 ( 0.004 ms): perf/4150 ... [continued]: perf_event_open()) = -1 EINVAL Invalid argument
41.018 ( 0.012 ms): perf/4150 perf_event_open(attr_uptr: 0x7ffebc8b5dd0, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
41.065 ( 0.011 ms): perf/4150 perf_event_open(attr_uptr: 0x3c7db78, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
41.080 ( 0.006 ms): perf/4150 perf_event_open(attr_uptr: 0x3c7db78, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
41.103 ( 0.010 ms): perf/4150 perf_event_open(attr_uptr: 0x3c4e748, pid: 4151 (perf), group_fd: -1, flags: FD_CLOEXEC) = 4
41.115 ( 0.006 ms): perf/4150 perf_event_open(attr_uptr: 0x3c4e748, pid: 4151 (perf), cpu: 1, group_fd: -1, flags: FD_CLOEXEC) = 5
41.122 ( 0.004 ms): perf/4150 perf_event_open(attr_uptr: 0x3c4e748, pid: 4151 (perf), cpu: 2, group_fd: -1, flags: FD_CLOEXEC) = 6
41.128 ( 0.008 ms): perf/4150 perf_event_open(attr_uptr: 0x3c4e748, pid: 4151 (perf), cpu: 3, group_fd: -1, flags: FD_CLOEXEC) = 8
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.017 MB perf.data (2 samples) ]
#
I.e. that return -EINVAL in x86_pmu_hw_config() is hit three times.
So fix it by just setting attr.sample_period
Now, after this patch:
# perf trace --max-stack=2 -e perf_event_open,probe:x86_pmu_hw_config* perf record usleep 1
[ perf record: Woken up 1 times to write data ]
0.000 ( 0.017 ms): perf/8469 perf_event_open(attr_uptr: 0x7ffe36c27d10, pid: -1, cpu: 3, group_fd: -1, flags: FD_CLOEXEC) = 4
syscall (/usr/lib64/libc-2.24.so)
perf_event_open_cloexec_flag (/home/acme/bin/perf)
0.050 ( 0.031 ms): perf/8469 perf_event_open(attr_uptr: 0x24ebb78, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
syscall (/usr/lib64/libc-2.24.so)
perf_evlist__config (/home/acme/bin/perf)
0.092 ( 0.040 ms): perf/8469 perf_event_open(attr_uptr: 0x24ebb78, pid: -1, group_fd: -1, flags: FD_CLOEXEC) = 4
syscall (/usr/lib64/libc-2.24.so)
perf_evlist__config (/home/acme/bin/perf)
0.143 ( 0.007 ms): perf/8469 perf_event_open(attr_uptr: 0x24bc748, cpu: -1, group_fd: -1 ) = 4
syscall (/usr/lib64/libc-2.24.so)
perf_event_attr__set_max_precise_ip (/home/acme/bin/perf)
0.161 ( 0.007 ms): perf/8469 perf_event_open(attr_uptr: 0x24bc748, pid: 8470 (perf), group_fd: -1, flags: FD_CLOEXEC) = 4
syscall (/usr/lib64/libc-2.24.so)
perf_evsel__open (/home/acme/bin/perf)
0.171 ( 0.005 ms): perf/8469 perf_event_open(attr_uptr: 0x24bc748, pid: 8470 (perf), cpu: 1, group_fd: -1, flags: FD_CLOEXEC) = 5
syscall (/usr/lib64/libc-2.24.so)
perf_evsel__open (/home/acme/bin/perf)
0.180 ( 0.007 ms): perf/8469 perf_event_open(attr_uptr: 0x24bc748, pid: 8470 (perf), cpu: 2, group_fd: -1, flags: FD_CLOEXEC) = 6
syscall (/usr/lib64/libc-2.24.so)
perf_evsel__open (/home/acme/bin/perf)
0.190 ( 0.005 ms): perf/8469 perf_event_open(attr_uptr: 0x24bc748, pid: 8470 (perf), cpu: 3, group_fd: -1, flags: FD_CLOEXEC) = 8
syscall (/usr/lib64/libc-2.24.so)
perf_evsel__open (/home/acme/bin/perf)
[ perf record: Captured and wrote 0.017 MB perf.data (7 samples) ]
#
The probe one called from perf_event_attr__set_max_precise_ip() works
the first time, with attr.precise_ip = 3, wit hthe next ones being the
per cpu ones for the cycles:ppp event.
And here is the text from a report and alternative proposed patch by
Thomas-Mich Richter:
---
On s390 the counter and sampling facility do not support a precise IP
skid level and sometimes returns EOPNOTSUPP when structure member
precise_ip in struct perf_event_attr is not set to zero.
On s390 commnd 'perf record -- true' fails with error EOPNOTSUPP. This
happens only when no events are specified on command line.
The functions called are
...
--> perf_evlist__add_default
--> perf_evsel__new_cycles
--> perf_event_attr__set_max_precise_ip
The last function determines the value of structure member precise_ip by
invoking the perf_event_open() system call and checking the return code.
The first successful open is the value for precise_ip.
However the value is determined without setting member sample_period and
indicates no sampling.
On s390 the counter facility and sampling facility are different. The
above procedure determines a precise_ip value of 3 using the counter
facility. Later it uses the sampling facility with a value of 3 and
fails with EOPNOTSUPP.
---
v2: Older compilers (e.g. gcc 4.4.7) don't support referencing members
of unnamed union members in the container struct initialization, so
move from:
struct perf_event_attr attr = {
...
.sample_period = 1,
};
to right after it as:
struct perf_event_attr attr = {
...
};
attr.sample_period = 1;
v3: We need to reset .sample_period to 0 to let the users of
perf_evsel__new_cycles() to properly setup attr.sample_period or
attr.sample_freq. Reported by Ingo Molnar.
Reported-and-Acked-by: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.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>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 18e7a45af91a ("perf/x86: Reject non sampling events with precise_ip")
Link: http://lkml.kernel.org/n/tip-yv6nnkl7tzqocrm0hl3x7vf1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The commit e7ee40475760 ("perf symbols: Fix symbols searching for module
in buildid-cache") added the function to check kernel modules reside in
the build-id cache. This was because there's no way to identify a DSO
which is actually a kernel module. So it searched linkname of the file
and find ".ko" suffix.
But this does not work for compressed kernel modules and now such DSOs
hCcave correct symtab_type now. So no need to check it anymore. This
patch essentially reverts the commit.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: kernel-team@lge.com
Link: http://lkml.kernel.org/r/20170608073109.30699-10-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The symsrc__init() overwrites dso->symtab_type as symsrc->type in dso__load_sym(). But for compressed kernel modules in the build-id cache, it should have original symtab type to be decompressed as needed. This fixes perf annotate to show disassembly of the function properly. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Cc: kernel-team@lge.com Link: http://lkml.kernel.org/r/20170608073109.30699-9-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If a kernel modules is compressed, it should be decompressed before running objdump to parse binary data correctly. This fixes a failure of object code reading test for me. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Cc: kernel-team@lge.com Link: http://lkml.kernel.org/r/20170608073109.30699-8-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
On failure, it should free the 'name', so clean up the error path using goto. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Cc: kernel-team@lge.com Link: http://lkml.kernel.org/r/20170608073109.30699-7-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Currently perf decompresses kernel modules when loading the symbol table but it missed to do it when reading raw data. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wang Nan <wangnan0@huawei.com> Cc: kernel-team@lge.com Link: http://lkml.kernel.org/r/20170608073109.30699-6-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>