linux_dsm_epyc7002/tools/perf/tests/dwarf-unwind.c

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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 21:07:57 +07:00
// SPDX-License-Identifier: GPL-2.0
#include <linux/compiler.h>
#include <linux/types.h>
#include <inttypes.h>
#include <unistd.h>
#include "tests.h"
#include "debug.h"
#include "machine.h"
#include "event.h"
perf tests: Fix compile when libunwind's unwind.h is available 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>
2017-09-06 22:02:09 +07:00
#include "../util/unwind.h"
#include "perf_regs.h"
#include "map.h"
#include "thread.h"
#include "callchain.h"
#if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__)
#include "arch-tests.h"
#endif
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
/* For bsearch. We try to unwind functions in shared object. */
#include <stdlib.h>
static int mmap_handler(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_mmap2_event(machine, event, sample);
}
static int init_live_machine(struct machine *machine)
{
union perf_event event;
pid_t pid = getpid();
return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
mmap_handler, machine, true, 500);
}
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
#define MAX_STACK 8
static int unwind_entry(struct unwind_entry *entry, void *arg)
{
unsigned long *cnt = (unsigned long *) arg;
char *symbol = entry->sym ? entry->sym->name : NULL;
static const char *funcs[MAX_STACK] = {
"test__arch_unwind_sample",
"unwind_thread",
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
"compare",
"bsearch",
"krava_3",
"krava_2",
"krava_1",
"test__dwarf_unwind"
};
/*
* The funcs[MAX_STACK] array index, based on the
* callchain order setup.
*/
int idx = callchain_param.order == ORDER_CALLER ?
MAX_STACK - *cnt - 1 : *cnt;
if (*cnt >= MAX_STACK) {
pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
return -1;
}
if (!symbol) {
pr_debug("failed: got unresolved address 0x%" PRIx64 "\n",
entry->ip);
return -1;
}
(*cnt)++;
pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n",
symbol, entry->ip, funcs[idx]);
return strcmp((const char *) symbol, funcs[idx]);
}
static noinline int unwind_thread(struct thread *thread)
{
struct perf_sample sample;
unsigned long cnt = 0;
int err = -1;
memset(&sample, 0, sizeof(sample));
if (test__arch_unwind_sample(&sample, thread)) {
pr_debug("failed to get unwind sample\n");
goto out;
}
err = unwind__get_entries(unwind_entry, &cnt, thread,
&sample, MAX_STACK);
if (err)
pr_debug("unwind failed\n");
else if (cnt != MAX_STACK) {
pr_debug("got wrong number of stack entries %lu != %d\n",
cnt, MAX_STACK);
err = -1;
}
out:
free(sample.user_stack.data);
free(sample.user_regs.regs);
return err;
}
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
static int global_unwind_retval = -INT_MAX;
static noinline int compare(void *p1, void *p2)
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
{
/* Any possible value should be 'thread' */
struct thread *thread = *(struct thread **)p1;
if (global_unwind_retval == -INT_MAX) {
/* Call unwinder twice for both callchain orders. */
callchain_param.order = ORDER_CALLER;
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
global_unwind_retval = unwind_thread(thread);
if (!global_unwind_retval) {
callchain_param.order = ORDER_CALLEE;
global_unwind_retval = unwind_thread(thread);
}
}
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
return p1 - p2;
}
static noinline int krava_3(struct thread *thread)
{
perf test: Fix dwarf unwind using libunwind. 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>
2015-01-14 09:36:47 +07:00
struct thread *array[2] = {thread, thread};
void *fp = &bsearch;
/*
* make _bsearch a volatile function pointer to
* prevent potential optimization, which may expand
* bsearch and call compare directly from this function,
* instead of libc shared object.
*/
void *(*volatile _bsearch)(void *, void *, size_t,
size_t, int (*)(void *, void *));
_bsearch = fp;
_bsearch(array, &thread, 2, sizeof(struct thread **), compare);
return global_unwind_retval;
}
static noinline int krava_2(struct thread *thread)
{
return krava_3(thread);
}
static noinline int krava_1(struct thread *thread)
{
return krava_2(thread);
}
int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused)
{
struct machine *machine;
struct thread *thread;
int err = -1;
machine = machine__new_host();
if (!machine) {
pr_err("Could not get machine\n");
return -1;
}
if (machine__create_kernel_maps(machine)) {
pr_err("Failed to create kernel maps\n");
return -1;
}
callchain_param.record_mode = CALLCHAIN_DWARF;
perf unwind: Do not look just at the global callchain_param.record_mode 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>
2018-01-16 02:48:46 +07:00
dwarf_callchain_users = true;
if (init_live_machine(machine)) {
pr_err("Could not init machine\n");
goto out;
}
if (verbose > 1)
machine__fprintf(machine, stderr);
thread = machine__find_thread(machine, getpid(), getpid());
if (!thread) {
pr_err("Could not get thread\n");
goto out;
}
err = krava_1(thread);
perf machine: Protect the machine->threads with a rwlock 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>
2015-04-07 06:43:22 +07:00
thread__put(thread);
out:
machine__delete_threads(machine);
machine__delete(machine);
return err;
}