Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753049AbbDBHe7 (ORCPT ); Thu, 2 Apr 2015 03:34:59 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:56370 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752220AbbDBHe5 (ORCPT ); Thu, 2 Apr 2015 03:34:57 -0400 X-AuditID: 85900ec0-a14c8b9000003d4c-83-551cf11924a1 Subject: [PATCH perf/core v2] perf-probe: Fix to track down unnamed union/structure members From: Masami Hiramatsu To: Arnaldo Carvalho de Melo Cc: Peter Zijlstra , Linux Kernel Mailing List , David Ahern , namhyung@kernel.org, Jiri Olsa , Ingo Molnar Date: Thu, 02 Apr 2015 16:33:12 +0900 Message-ID: <20150402073312.14482.37942.stgit@localhost.localdomain> In-Reply-To: <20150401144111.GA4549@kernel.org> References: <20150401144111.GA4549@kernel.org> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3324 Lines: 90 Fix perf probe to track down unnamed union/structure members. perf probe did not track down the tree of unnamed union/structure members, since it just failed to find given "name" in a parent structure/union. To solve this issue, I've introduced 2 changes. - Fix die_find_member() to track down the type-DIE if it is unnamed, and if it contains the specified member, returns the unnamed member. (note that we don't return found member, since unnamed member has the offset in the parent structure) - Fix convert_variable_fields() to track down the unnamed union/ structure (one-by-one). With this patch, perf probe can access unnamed fields. ----- #./perf probe -nfx ./perf lock__delete ops 'locked_ops=ops->locked.ops' Added new event: probe_perf:lock__delete (on lock__delete in /home/mhiramat/ksrc/linux-3/tools/perf/perf with ops locked_ops=ops->locked.ops) You can now use it in all perf tools, such as: perf record -e probe_perf:lock__delete -aR sleep 1 ----- The original report of this issue is: https://lkml.org/lkml/2015/3/5/431 Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Masami Hiramatsu --- tools/perf/util/dwarf-aux.c | 14 ++++++++++---- tools/perf/util/probe-finder.c | 8 +++++++- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 780b2bc..c34e024 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -801,10 +801,16 @@ static int __die_find_member_cb(Dwarf_Die *die_mem, void *data) { const char *name = data; - if ((dwarf_tag(die_mem) == DW_TAG_member) && - die_compare_name(die_mem, name)) - return DIE_FIND_CB_END; - + if (dwarf_tag(die_mem) == DW_TAG_member) { + if (die_compare_name(die_mem, name)) + return DIE_FIND_CB_END; + else if (!dwarf_diename(die_mem)) { /* Unnamed structure */ + Dwarf_Die type_die, tmp_die; + if (die_get_type(die_mem, &type_die) && + die_find_member(&type_die, name, &tmp_die)) + return DIE_FIND_CB_END; + } + } return DIE_FIND_CB_SIBLING; } diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 46f009a..7831e2d 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -460,7 +460,8 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, " nor array.\n", varname); return -EINVAL; } - if (field->ref) { + /* While prcessing unnamed field, we don't care about this */ + if (field->ref && dwarf_diename(vr_die)) { pr_err("Semantic error: %s must be referred by '.'\n", field->name); return -EINVAL; @@ -491,6 +492,11 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, } ref->offset += (long)offs; + /* If this member is unnamed, we need to reuse this field */ + if (!dwarf_diename(die_mem)) + return convert_variable_fields(die_mem, varname, field, + &ref, die_mem); + next: /* Converting next field */ if (field->next) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/