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

[Thomas Backlund]

Den 29-12-2019 kl. 20:42, skrev Thomas Backlund:
> Den 29-12-2019 kl. 19:24, skrev Greg Kroah-Hartman:
> > From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> >
> > [ 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:
> >
> > ÂÂ # perf probe -l
> > ÂÂÂÂ probe:clear_tasks_mm_cpumask (on 
> > clear_tasks_mm_cpumask+18446744071579263632@work/linux/linux/kernel/cpu.c) 
> >
> > ÂÂÂÂ probe:clear_tasks_mm_cpumask_1 (on 
> > clear_tasks_mm_cpumask+18446744071579263752@work/linux/linux/kernel/cpu.c) 
> >
> >
> > With this:
> >
> > ÂÂ # perf probe -l
> > ÂÂÂÂ probe:clear_tasks_mm_cpumask (on 
> > clear_tasks_mm_cpumask@work/linux/linux/kernel/cpu.c)
> > ÂÂÂÂ probe:clear_tasks_mm_cpumask_1 (on 
> > clear_tasks_mm_cpumask:21@work/linux/linux/kernel/cpu.c)
> >
> > Committer testing:
> >
> > Before:
> >
> > ÂÂ [root@quaco ~]# perf probe -l
> > ÂÂÂÂ probe:clear_tasks_mm_cpumask (on 
> > clear_tasks_mm_cpumask+18446744071579765152@kernel/cpu.c)
> > ÂÂ [root@quaco ~]#
> >
> > After:
> >
> > ÂÂ [root@quaco ~]# perf probe -l
> > ÂÂÂÂ probe:clear_tasks_mm_cpumask (on 
> > clear_tasks_mm_cpumask@kernel/cpu.c)
> > ÂÂ [root@quaco ~]#
> >
> > Fixes: 1d46ea2a6a40 ("perf probe: Fix listing incorrect line number 
> > with inline function")
> > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> > Link: 
> > http://lore.kernel.org/lkml/157199321227.8075.14655572419136993015.stgit@devnote2 
> >
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> > Â tools/perf/util/probe-finder.c | 4 ++--
> > Â 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,
> > ÂÂÂÂÂÂÂÂÂ /* Get function entry information */
> > ÂÂÂÂÂÂÂÂÂ func = basefunc = dwarf_diename(&spdie);
> > ÂÂÂÂÂÂÂÂÂ if (!func ||
> > -ÂÂÂÂÂÂÂÂÂÂÂ dwarf_entrypc(&spdie, &baseaddr) != 0 ||
> > +ÂÂÂÂÂÂÂÂÂÂÂ die_entrypc(&spdie, &baseaddr) != 0 ||
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ dwarf_decl_line(&spdie, &baseline) != 0) {
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ lineno = 0;
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ goto post;
> > @@ -1595,7 +1595,7 @@ int debuginfo__find_probe_point(struct debuginfo 
> > *dbg, unsigned long addr,
> > ÂÂÂÂÂÂÂÂÂ while (die_find_top_inlinefunc(&spdie, (Dwarf_Addr)addr,
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ &indie)) {
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ /* There is an inline function */
> > -ÂÂÂÂÂÂÂÂÂÂÂ if (dwarf_entrypc(&indie, &_addr) == 0 &&
> > +ÂÂÂÂÂÂÂÂÂÂÂ if (die_entrypc(&indie, &_addr) == 0 &&
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ _addr == addr) {
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ /*
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ * 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'


And the fix for the perf build errors I reported against:
[PATCH 5.4 245/434] perf probe: Fix to list probe event with correct 
line number
[PATCH 5.4 248/434] perf probe: Fix to probe an inline function which 
has no entry pc
[PATCH 5.4 249/434] perf probe: Fix to show ranges of variables in 
functions without entry_pc
[PATCH 5.4 250/434] perf probe: Fix to show inlined function callsite 
without entry_pc
[PATCH 5.4 252/434] perf probe: Fix to probe a function which has no 
entry pc

is to add the missing:

From 91e2f539eeda26ab00bd03fae8dc434c128c85ed Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Date: Thu, 24 Oct 2019 18:12:54 +0900
Subject: [PATCH] perf probe: Fix to show function entry line as probe-able


--
Thomas