Re: [PATCH 5.4 249/434] perf probe: Fix to show ranges of variables in functions without entry_pc

Thomas Backlund
2019-12-29T18:34:54Z

Den 29-12-2019 kl. 19:25, skrev Greg Kroah-Hartman:
> From: Masami Hiramatsu <mhiramat@kernel.org>
>
> [ Upstream commit af04dd2f8ebaa8fbd46f698714acbf43da14da45 ]
>
> Fix to show ranges of variables (--range and --vars option) in functions
> which DIE has only ranges but no entry_pc attribute.
>
> Without this fix:
>
> # perf probe --range -V clear_tasks_mm_cpumask
> Available variables at clear_tasks_mm_cpumask
> @<clear_tasks_mm_cpumask+0>
> (No matched variables)
>
> With this fix:
>
> # perf probe --range -V clear_tasks_mm_cpumask
> Available variables at clear_tasks_mm_cpumask
> @<clear_tasks_mm_cpumask+0>
> [VAL] int cpu @<clear_tasks_mm_cpumask+[0-35,317-317,2052-2059]>
>
> Committer testing:
>
> Before:
>
> [root@quaco ~]# perf probe --range -V clear_tasks_mm_cpumask
> Available variables at clear_tasks_mm_cpumask
> @<clear_tasks_mm_cpumask+0>
> (No matched variables)
> [root@quaco ~]#
>
> After:
>
> [root@quaco ~]# perf probe --range -V clear_tasks_mm_cpumask
> Available variables at clear_tasks_mm_cpumask
> @<clear_tasks_mm_cpumask+0>
> [VAL] int cpu @<clear_tasks_mm_cpumask+[0-23,23-105,105-106,106-106,1843-1850,1850-1862]>
> [root@quaco ~]#
>
> Using it:
>
> [root@quaco ~]# perf probe clear_tasks_mm_cpumask cpu
> Added new event:
> probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask with cpu)
>
> You can now use it in all perf tools, such as:
>
> perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1
>
> [root@quaco ~]# perf probe -l
> probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c with cpu)
> [root@quaco ~]#
> [root@quaco ~]# perf trace -e probe:*cpumask
> ^C[root@quaco ~]#
>
> Fixes: 349e8d261131 ("perf probe: Add --range option to show a variable's location range")
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Link: http://lore.kernel.org/lkml/157199323018.8075.8179744380479673672.stgit@devnote2
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> tools/perf/util/dwarf-aux.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
> index 929b7c0567f4..4b1890204e99 100644
> --- a/tools/perf/util/dwarf-aux.c
> +++ b/tools/perf/util/dwarf-aux.c
> @@ -997,7 +997,7 @@ static int die_get_var_innermost_scope(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
> bool first = true;
> const char *name;
>
> - ret = dwarf_entrypc(sp_die, &entry);
> + ret = die_entrypc(sp_die, &entry);
> if (ret)
> return ret;
>
> @@ -1060,7 +1060,7 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
> bool first = true;
> const char *name;
>
> - ret = dwarf_entrypc(sp_die, &entry);
> + ret = die_entrypc(sp_die, &entry);
> if (ret)
> return ret;
>
>

Still broken...

/usr/bin/ld: perf-in.o: in function `die_get_var_range':
/work/rpmbuild/BUILD/kernel-x86_64/linux-5.4/tools/perf/util/dwarf-aux.c:1085:
undefined reference to `die_entrypc'
/usr/bin/ld: perf-in.o: in function `die_get_var_innermost_scope':
/work/rpmbuild/BUILD/kernel-x86_64/linux-5.4/tools/perf/util/dwarf-aux.c:1022:
undefined reference to `die_entrypc'
collect2: error: ld returned 1 exit status

--
Thomas