Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758553AbbDYIOw (ORCPT ); Sat, 25 Apr 2015 04:14:52 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:7211 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758372AbbDYIOs (ORCPT ); Sat, 25 Apr 2015 04:14:48 -0400 From: He Kuang To: , , , , CC: , Subject: [PATCH] perf probe: Fix bug in perf probe with global variables Date: Sat, 25 Apr 2015 16:08:58 +0800 Message-ID: <1429949338-18678-1-git-send-email-hekuang@huawei.com> X-Mailer: git-send-email 2.3.3.220.g9ab698f MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.189] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2312 Lines: 62 There are missing curly braces which causes find_variable() return wrong value when probing with global variables. This problem can be reproduced as following: $ perf probe -v --add='generic_perform_write global_variable_for_test' ... Try to find probe point from debuginfo. Probe point found: generic_perform_write+0 Searching 'global_variable_for_test' variable in context. An error occurred in debuginfo analysis (-2). Error: Failed to add events. Reason: No such file or directory (Code: -2) After this patch: $ perf probe -v --add='generic_perform_write global_variable_for_test' ... Converting variable global_variable_for_test into trace event. global_variable_for_test type is int. Found 1 probe_trace_events. Opening /sys/kernel/debug/tracing/kprobe_events write=1 Added new event: Writing event: p:probe/generic_perform_write _stext+1237464 global_variable_for_test=@global_variable_for_test+0:s32 probe:generic_perform_write (on generic_perform_write with global_variable_for_test) You can now use it in all perf tools, such as: perf record -e probe:generic_perform_write -aR sleep 1 Signed-off-by: He Kuang --- tools/perf/util/probe-finder.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index 44554c3..1c3cc07 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -578,10 +578,12 @@ static int find_variable(Dwarf_Die *sc_die, struct probe_finder *pf) /* Search child die for local variables and parameters. */ if (!die_find_variable_at(sc_die, pf->pvar->var, pf->addr, &vr_die)) { /* Search again in global variables */ - if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, 0, &vr_die)) + if (!die_find_variable_at(&pf->cu_die, pf->pvar->var, + 0, &vr_die)) { pr_warning("Failed to find '%s' in this function.\n", pf->pvar->var); ret = -ENOENT; + } } if (ret >= 0) ret = convert_variable(&vr_die, pf); -- 1.8.5.2 -- 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/