Re: [PATCH 5.4 245/434] perf probe: Fix to list probe event with correct line number

Thomas Backlund
2019-12-29T18:42:34Z

Den 29-12-2019 kl. 19:24, skrev Greg Kroah-Hartman:
> From: Masami Hiramatsu <mhiramat@kernel.org>
>
> [ Upstream commit 3895534dd78f0fd4d3f9e05ee52b9cdd444a743e ]
>
> Since debuginfo__find_probe_point() uses dwarf_entrypc() for finding the
> entry address of the function on which a probe is, it will fail when the
> function DIE has only ranges attribute.
>
> To fix this issue, use die_entrypc() instead of dwarf_entrypc().
>
> Without this fix, perf probe -l shows incorrect offset:
>
> # perf probe -l
> probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask+18446744071579263632@work/linux/linux/kernel/cpu.c)
> probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask+18446744071579263752@work/linux/linux/kernel/cpu.c)
>
> With this:
>
> # perf probe -l
> probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@work/linux/linux/kernel/cpu.c)
> probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask:21@work/linux/linux/kernel/cpu.c)
>
> Committer testing:
>
> Before:
>
> [root@quaco ~]# perf probe -l
> probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask+18446744071579765152@kernel/cpu.c)
> [root@quaco ~]#
>
> After:
>
> [root@quaco ~]# perf probe -l
> probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c)
> [root@quaco ~]#
>
> Fixes: 1d46ea2a6a40 ("perf probe: Fix listing incorrect line number with inline function")
> 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/157199321227.8075.14655572419136993015.stgit@devnote2
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> tools/perf/util/probe-finder.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index cd9f95e5044e..7c8d30fb2b99 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1578,7 +1578,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
> /* Get function entry information */
> func = basefunc = dwarf_diename(&spdie);
> if (!func ||
> - dwarf_entrypc(&spdie, &baseaddr) != 0 ||
> + die_entrypc(&spdie, &baseaddr) != 0 ||
> dwarf_decl_line(&spdie, &baseline) != 0) {
> lineno = 0;
> goto post;
> @@ -1595,7 +1595,7 @@ int debuginfo__find_probe_point(struct debuginfo *dbg, unsigned long addr,
> while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
> &indie)) {
> /* There is an inline function */
> - if (dwarf_entrypc(&indie, &_addr) == 0 &&
> + if (die_entrypc(&indie, &_addr) == 0 &&
> _addr == addr) {
> /*
> * addr is at an inline function entry.
>

still broken

/usr/bin/ld: perf-in.o: in function `debuginfo__find_probe_point':
/work/rpmbuild/BUILD/kernel-x86_64/linux-5.4/tools/perf/util/probe-finder.c:1616:
undefined reference to `die_entrypc'

--
Thomas