From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752282AbeCTGgl (ORCPT ); Tue, 20 Mar 2018 02:36:41 -0400 Received: from terminus.zytor.com ([198.137.202.136]:56397 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751450AbeCTGgh (ORCPT ); Tue, 20 Mar 2018 02:36:37 -0400 Date: Mon, 19 Mar 2018 23:36:17 -0700 From: tip-bot for Masami Hiramatsu Message-ID: Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org, shuah@kernel.org, acme@redhat.com, mingo@kernel.org, mhiramat@kernel.org, ravi.bangoria@linux.vnet.ibm.com, tom.zanussi@linux.intel.com, hpa@zytor.com, tglx@linutronix.de, namhyung@kernel.org Reply-To: ravi.bangoria@linux.vnet.ibm.com, hpa@zytor.com, tom.zanussi@linux.intel.com, tglx@linutronix.de, namhyung@kernel.org, rostedt@goodmis.org, shuah@kernel.org, linux-kernel@vger.kernel.org, acme@redhat.com, mingo@kernel.org, mhiramat@kernel.org In-Reply-To: <152129114502.31874.2474068470011496356.stgit@devbox> References: <152129114502.31874.2474068470011496356.stgit@devbox> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf probe: Use right type to access array elements Git-Commit-ID: d0461794a1dcaf552b507e23788777f718b736a1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: d0461794a1dcaf552b507e23788777f718b736a1 Gitweb: https://git.kernel.org/tip/d0461794a1dcaf552b507e23788777f718b736a1 Author: Masami Hiramatsu AuthorDate: Sat, 17 Mar 2018 21:52:25 +0900 Committer: Arnaldo Carvalho de Melo CommitDate: Mon, 19 Mar 2018 13:51:53 -0300 perf probe: Use right type to access array elements Current 'perf probe' converts the type of array-elements incorrectly. It always converts the types as a pointer of array. This passes the "array" type DIE to the type converter so that it can get correct "element of array" type DIE from it. E.g. ==== $ cat hello.c #include void foo(int a[]) { printf("%d\n", a[1]); } void main() { int a[3] = {4, 5, 6}; printf("%d\n", a[0]); foo(a); } $ gcc -g hello.c -o hello $ perf probe -x ./hello -D "foo a[1]" ==== Without this fix, above outputs ==== p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):u64 ==== The "u64" means "int *", but a[1] is "int". With this, ==== p:probe_hello/foo /tmp/hello:0x4d3 a=+4(-8(%bp)):s32 ==== So, "int" correctly converted to "s32" Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Shuah Khan Cc: Steven Rostedt Cc: Tom Zanussi Cc: linux-kselftest@vger.kernel.org Cc: linux-trace-users@vger.kernel.org Fixes: b2a3c12b7442 ("perf probe: Support tracing an entry of array") Link: http://lkml.kernel.org/r/152129114502.31874.2474068470011496356.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/probe-finder.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c index a5731de0e5eb..c37fbef1711d 100644 --- a/tools/perf/util/probe-finder.c +++ b/tools/perf/util/probe-finder.c @@ -423,20 +423,20 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } - pr_debug2("Var real type: (%x)\n", (unsigned)dwarf_dieoffset(&type)); + pr_debug2("Var real type: %s (%x)\n", dwarf_diename(&type), + (unsigned)dwarf_dieoffset(&type)); tag = dwarf_tag(&type); if (field->name[0] == '[' && (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)) { - if (field->next) - /* Save original type for next field */ - memcpy(die_mem, &type, sizeof(*die_mem)); + /* Save original type for next field or type */ + memcpy(die_mem, &type, sizeof(*die_mem)); /* Get the type of this array */ if (die_get_real_type(&type, &type) == NULL) { pr_warning("Failed to get the type of %s.\n", varname); return -ENOENT; } - pr_debug2("Array real type: (%x)\n", + pr_debug2("Array real type: %s (%x)\n", dwarf_diename(&type), (unsigned)dwarf_dieoffset(&type)); if (tag == DW_TAG_pointer_type) { ref = zalloc(sizeof(struct probe_trace_arg_ref)); @@ -448,9 +448,6 @@ static int convert_variable_fields(Dwarf_Die *vr_die, const char *varname, *ref_ptr = ref; } ref->offset += dwarf_bytesize(&type) * field->index; - if (!field->next) - /* Save vr_die for converting types */ - memcpy(die_mem, vr_die, sizeof(*die_mem)); goto next; } else if (tag == DW_TAG_pointer_type) { /* Check the pointer and dereference */